Mini-XML Programmers Manual, Version 2.5
Author: Michael R. Sweet

# Table of Contents

Introduction

- Organization of This Document
- Notation Conventions
- Abbreviations
- Other References
- Legal Stuff

Building, Installing, and Packaging Mini-XML

- Compiling Mini-XML
  - Compiling with Visual C++
  - Compiling with Command-Line Tools
- Installing Mini-XML
- Creating Mini-XML Packages

Getting Started with Mini-XML

- The Basics
- Nodes
- Creating XML Documents
- Loading XML
- Saving XML
  - Controlling Line Wrapping
- Finding and Iterating Nodes

More Mini-XML Programming Techniques

- Load Callbacks
- Save Callbacks
- Custom Data Types
- Changing Node Values
- Formatted Text
- Indexing
- SAX (Stream) Loading of Documents

Using the mxmldoc Utility

- The Basics
- Commenting Your Code
- Titles, Sections, and Introductions

Mini-XML License
Release Notes

Library Reference

- Contents
- Functions
  - mxmlAdd
  - mxmlDelete
  - mxmlElementDeleteAttr
  - mxmlElementGetAttr
  - mxmlElementSetAttr
  - mxmlElementSetAttrf
  - mxmlEntityAddCallback
  - mxmlEntityGetName
  - mxmlEntityGetValue
  - mxmlEntityRemoveCallback
  - mxmlFindElement
  - mxmlIndexDelete
  - mxmlIndexEnum
  - mxmlIndexFind
  - mxmlIndexNew
  - mxmlIndexReset
  - mxmlLoadFd
  - mxmlLoadFile
  - mxmlLoadString
  - mxmlNewCDATA
  - mxmlNewCustom
  - mxmlNewElement
  - mxmlNewInteger
  - mxmlNewOpaque
  - mxmlNewReal
  - mxmlNewText
  - mxmlNewTextf
  - mxmlNewXML
  - mxmlRelease
  - mxmlRemove
  - mxmlRetain
  - mxmlSAXLoadFd
  - mxmlSAXLoadFile
  - mxmlSAXLoadString
  - mxmlSaveAllocString
  - mxmlSaveFd
  - mxmlSaveFile
  - mxmlSaveString
  - mxmlSetCDATA
  - mxmlSetCustom
  - mxmlSetCustomHandlers
  - mxmlSetElement
  - mxmlSetErrorCallback
  - mxmlSetInteger
  - mxmlSetOpaque
  - mxmlSetReal
  - mxmlSetText
  - mxmlSetTextf
  - mxmlSetWrapMargin
  - mxmlWalkNext
  - mxmlWalkPrev
- Data Types
  - mxml_attr_t
  - mxml_custom_destroy_cb_t
  - mxml_custom_load_cb_t
  - mxml_custom_save_cb_t
  - mxml_custom_t
  - mxml_element_t
  - mxml_error_cb_t
  - mxml_index_t
  - mxml_load_cb_t
  - mxml_node_t
  - mxml_save_cb_t
  - mxml_sax_cb_t
  - mxml_sax_event_t
  - mxml_text_t
  - mxml_value_t
- Structures
  - mxml_attr_s
  - mxml_custom_s
  - mxml_element_s
  - mxml_index_s
  - mxml_node_s
  - mxml_text_s
- Unions
  - mxml_value_u
- Constants
  - mxml_sax_event_e
  - mxml_type_e

XML Schema

# Introduction

This programmers manual describes Mini-XML version 2.5, a small XML parsing library that you can use to read and write XML data files in your C and C++ applications.

Mini-XML was initially developed for the Gutenprint project to replace the rather large and unwieldy `libxml2` library with something substantially smaller and easier-to-use. It all began one morning in June of 2003 when Robert posted the following sentence to the developer's list:

> It's bad enough that we require libxml2, but rolling our own XML parser is a bit more than we can handle.

I then replied with:

> Given the limited scope of what you use in XML, it should be trivial to code a mini-XML API in a few hundred lines of code.

I took my own challenge and coded furiously for two days to produced the initial public release of Mini-XML, total lines of code: 696. Robert promptly integrated Mini-XML into Gutenprint and removed libxml2.

Thanks to lots of feedback and support from various developers, Mini-XML has evolved since then to provide a more complete XML implementation and now stands at a whopping 3,441 lines of code, compared to 103,893 lines of code for libxml2 version 2.6.9.

Aside from Gutenprint, Mini-XML is used for the following projects/software applications:

- Common UNIX Printing System
- CUPS Driver Development Kit
- ZynAddSubFX

Please email me (mxml @ easysw . com) if you would like your project added or removed from this list, or if you have any comments/quotes you would like me to publish about your experiences with Mini-XML.

## Organization of This Document

This manual is organized into the following chapters and appendices:

- Chapter 1, "Building, Installing, and Packaging Mini-XML", provides compilation, installation, and packaging instructions for Mini-XML.
- Chapter 2, "Getting Started with Mini-XML", shows how to use the Mini-XML library in your programs.
- Chapter 3, "More Mini-XML Programming Techniques ", shows additional ways to use the Mini-XML library.
- Chapter 4, "Using the mxmldoc Utility", describes how to use the `mxmldoc(1)` program to generate software documentation.
- Appendix A, "Mini-XML License", provides the terms and conditions for using and distributing Mini-XML.
- Appendix B, "Release Notes", lists the changes in each release of Mini-XML.
- Appendix C, "Library Reference", contains a complete reference for Mini-XML, generated by `mxmldoc`.
- Appendix D, "XML Schema", shows the XML schema used for the XML files produced by `mxmldoc`.

## Notation Conventions

Various font and syntax conventions are used in this guide. Examples and their meanings and uses are explained below:

`lpstat`
`lpstat(1)`
  The names of commands; the first mention of a command or function in a chapter is followed by a manual page section number.
/var
/usr/share/cups/data/testprint.ps
  File and directory names.
`Request ID is Printer-123`
  Screen output.
`lp -d printer filename ENTER`
  Literal user input; special keys like `ENTER` are in ALL CAPS.
12.3
  Numbers in the text are written using the period (.) to indicate the decimal point.

## Abbreviations

The following abbreviations are used throughout this manual:

Gb
  Gigabytes, or 1073741824 bytes
kb
  Kilobytes, or 1024 bytes
Mb
  Megabytes, or 1048576 bytes
UTF-8, UTF-16
  Unicode Transformation Format, 8-bit or 16-bit
W3C
  World Wide Web Consortium
XML
  Extensible Markup Language

## Other References

The Unicode Standard, Version 4.0, Addison-Wesley, ISBN 0-321-18578-1
  The definition of the Unicode character set which is used for XML.
Extensible Markup Language (XML) 1.0 (Third Edition)
  The XML specification from the World Wide Web Consortium (W3C)

## Legal Stuff

The Mini-XML library is copyright 2003-2008 by Michael Sweet.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details.

# Building, Installing, and Packaging Mini-XML

This chapter describes how to build, install, and package Mini-XML on your system from the source archive. You will need an ANSI/ISO-C compatible compiler to build Mini-XML - GCC works, as do most vendors' C compilers. If you are building Mini-XML on Windows, we recommend using the Visual C++ environment with the supplied solution file. For other operating systems, you'll need a POSIX-compatible shell and `make` program in addition to the C compiler.

## Compiling Mini-XML

Mini-XML comes with both an autoconf-based configure script and a Visual C++ solution that can be used to compile the library and associated tools.

### Compiling with Visual C++

Open the mxml.sln solution in the vcnet folder. Choose the desired build configuration, "Debug" (the default) or "Release", and then choose Build Solution from the Build menu.

### Compiling with Command-Line Tools

Type the following command to configure the Mini-XML source code for your system:

        ./configure ENTER

The default install prefix is /usr/local, which can be overridden using the `--prefix` option:

        ./configure --prefix=/foo ENTER

Other configure options can be found using the `--help` option:

        ./configure --help ENTER

Once you have configured the software, use the `make(1)` program to do the build and run the test program to verify that things are working, as follows:

        make ENTER

## Installing Mini-XML

If you are using Visual C++, copy the mxml.lib and and mxml.h files to the Visual C++ lib and include directories, respectively.

Otherwise, use the `make` command with the `install` target to install Mini-XML in the configured directories:

        make install ENTER

## Creating Mini-XML Packages

Mini-XML includes two files that can be used to create binary packages. The first file is mxml.spec which is used by the `rpmbuild(8)` software to create Red Hat Package Manager ("RPM") packages which are commonly used on Linux. Since `rpmbuild` wants to compile the software on its own, you can provide it with the Mini-XML tar file to build the package:

        rpmbuild -ta mxml-version.tar.gz ENTER

The second file is mxml.list which is used by the `epm(1)` program to create software packages in a variety of formats. The `epm` program is available from the following URL:

        http://www.easysw.com/epm/

Use the `make` command with the `epm` target to create portable and native packages for your system:

        make epm ENTER

The packages are stored in a subdirectory named dist for your convenience. The portable packages utilize scripts and tar files to install the software on the target system. After extracting the package archive, use the mxml.install script to install the software.

The native packages will be in the local OS's native format: RPM for Red Hat Linux, DPKG for Debian Linux, PKG for Solaris, and so forth. Use the corresponding commands to install the native packages.

# Getting Started with Mini-XML

This chapter describes how to write programs that use Mini-XML to access data in an XML file. Mini-XML provides the following functionality:

- Functions for creating and managing XML documents in memory.
- Reading of UTF-8 and UTF-16 encoded XML files and strings.
- Writing of UTF-8 encoded XML files and strings.
- Support for arbitrary element names, attributes, and attribute values with no preset limits, just available memory.
- Support for integer, real, opaque ("cdata"), and text data types in "leaf" nodes.
- "Find", "index", and "walk" functions for easily accessing data in an XML document.

Mini-XML doesn't do validation or other types of processing on the data based upon schema files or other sources of definition information, nor does it support character entities other than those required by the XML specification.

## The Basics

Mini-XML provides a single header file which you include:

        #include <mxml.h>

The Mini-XML library is included with your program using the `-lmxml` option:

        gcc -o myprogram myprogram.c -lmxml ENTER

If you have the `pkg-config(1)` software installed, you can use it to determine the proper compiler and linker options for your installation:

        pkg-config --cflags mxml ENTER
        pkg-config --libs mxml ENTER

## Nodes

Every piece of information in an XML file (elements, text, numbers) is stored in memory in "nodes". Nodes are defined by the `mxml_node_t` structure. The `type` member defines the node type (element, integer, opaque, real, or text) which determines which value you want to look at in the `value` union.

Table 2-1: Mini-XML Node Value Members
Value | Type | Node member
--- | --- | ---
Custom | `void *` | `node->value.custom.data`
Element | `char *` | `node->value.element.name`
Integer | `int` | `node->value.integer`
Opaque (string) | `char *` | `node->value.opaque`
Real | `double` | `node->value.real`
Text | `char *` | `node->value.text.string`

Each node also has a `user_data` member which allows you to associate application-specific data with each node as needed.

New nodes are created using the `mxmlNewElement`, `mxmlNewInteger` , `mxmlNewOpaque`, `mxmlNewReal`, `mxmlNewText` `mxmlNewTextf` `mxmlNewXML` functions. Only elements can have child nodes, and the top node must be an element, usually the `<?xml version="1.0"?>` node created by `mxmlNewXML()`.

Nodes have pointers to the node above (`parent`), below (`child`), left (`prev`), and right (`next`) of the current node. If you have an XML file like the following:

        <?xml version="1.0"?>
        <data>
            <node>val1</node>
            <node>val2</node>
            <node>val3</node>
            <group>
                <node>val4</node>
                <node>val5</node>
                <node>val6</node>
            </group>
            <node>val7</node>
            <node>val8</node>
        </data>

the node tree for the file would look like the following in memory:

        ?xml
          |
        data
          |
        node - node - node - group - node - node
          |      |      |      |       |      |
        val1   val2   val3     |     val7   val8
                               |
                             node - node - node
                               |      |      |
                             val4   val5   val6

where "-" is a pointer to the next node and "|" is a pointer to the first child node.

Once you are done with the XML data, use the `mxmlDelete` function to recursively free the memory that is used for a particular node or the entire tree:

        mxmlDelete(tree);

## Creating XML Documents

You can create and update XML documents in memory using the various `mxmlNew` functions. The following code will create the XML document described in the previous section:

        mxml_node_t *xml;    /* <?xml ... ?> */
        mxml_node_t *data;   /* <data> */
        mxml_node_t *node;   /* <node> */
        mxml_node_t *group;  /* <group> */

        xml = mxmlNewXML("1.0");

        data = mxmlNewElement(xml, "data");

            node = mxmlNewElement(data, "node");
            mxmlNewText(node, 0, "val1");
            node = mxmlNewElement(data, "node");
            mxmlNewText(node, 0, "val2");
            node = mxmlNewElement(data, "node");
            mxmlNewText(node, 0, "val3");

            group = mxmlNewElement(data, "group");

                node = mxmlNewElement(group, "node");
                mxmlNewText(node, 0, "val4");
                node = mxmlNewElement(group, "node");
                mxmlNewText(node, 0, "val5");
                node = mxmlNewElement(group, "node");
                mxmlNewText(node, 0, "val6");

            node = mxmlNewElement(data, "node");
            mxmlNewText(node, 0, "val7");
            node = mxmlNewElement(data, "node");
            mxmlNewText(node, 0, "val8");

We start by creating the `<?xml version="1.0"?>` node common to all XML files using the `mxmlNewXML` function:

        xml = mxmlNewXML("1.0");

We then create the `<data>` node used for this document using the `mxmlNewElement` function. The first argument specifies the parent node (`xml`) while the second specifies the element name (`data`):

        data = mxmlNewElement(xml, "data");

Each `<node>...</node>` in the file is created using the `mxmlNewElement` and `mxmlNewText` functions. The first argument of `mxmlNewText` specifies the parent node (`node`). The second argument specifies whether whitespace appears before the text - 0 or false in this case. The last argument specifies the actual text to add:

        node = mxmlNewElement(data, "node");
        mxmlNewText(node, 0, "val1");

The resulting in-memory XML document can then be saved or processed just like one loaded from disk or a string.

## Loading XML

You load an XML file using the `mxmlLoadFile` function:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "r");
        tree = mxmlLoadFile(NULL, fp,
                            MXML_TEXT_CALLBACK);
        fclose(fp);

The first argument specifies an existing XML parent node, if any. Normally you will pass `NULL` for this argument unless you are combining multiple XML sources. The XML file must contain a complete XML document including the `?xml` element if the parent node is `NULL`.

The second argument specifies the stdio file to read from, as opened by `fopen()` or `popen()`. You can also use `stdin` if you are implementing an XML filter program.

The third argument specifies a callback function which returns the value type of the immediate children for a new element node: `MXML_CUSTOM`, `MXML_IGNORE`, `MXML_INTEGER`, `MXML_OPAQUE`, `MXML_REAL`, or `MXML_TEXT`. Load callbacks are described in detail in Chapter 3. The example code uses the `MXML_TEXT_CALLBACK` constant which specifies that all data nodes in the document contain whitespace-separated text values. Other standard callbacks include `MXML_IGNORE_CALLBACK`, `MXML_INTEGER_CALLBACK`, `MXML_OPAQUE_CALLBACK`, and `MXML_REAL_CALLBACK`.

The `mxmlLoadString` function loads XML node trees from a string:

        char buffer[8192];
        mxml_node_t *tree;

        ...
        tree = mxmlLoadString(NULL, buffer,
                              MXML_TEXT_CALLBACK);

The first and third arguments are the same as used for `mxmlLoadFile()`. The second argument specifies the string or character buffer to load and must be a complete XML document including the `?xml` element if the parent node is `NULL`.

## Saving XML

You save an XML file using the `mxmlSaveFile` function:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "w");
        mxmlSaveFile(tree, fp, MXML_NO_CALLBACK);
        fclose(fp);

The first argument is the XML node tree to save. It should normally be a pointer to the top-level `?xml` node in your XML document.

The second argument is the stdio file to write to, as opened by `fopen()` or `popen()`. You can also use `stdout` if you are implementing an XML filter program.

The third argument is the whitespace callback to use when saving the file. Whitespace callbacks are covered in detail in Chapter 3. The previous example code uses the `MXML_NO_CALLBACK` constant to specify that no special whitespace handling is required.

The `mxmlSaveAllocString`, and `mxmlSaveString` functions save XML node trees to strings:

        char buffer[8192];
        char *ptr;
        mxml_node_t *tree;

        ...
        mxmlSaveString(tree, buffer, sizeof(buffer),
                       MXML_NO_CALLBACK);

        ...
        ptr = mxmlSaveAllocString(tree, MXML_NO_CALLBACK);

The first and last arguments are the same as used for `mxmlSaveFile()`. The `mxmlSaveString` function takes pointer and size arguments for saving the XML document to a fixed-size buffer, while `mxmlSaveAllocString()` returns a string buffer that was allocated using `malloc()`.

### Controlling Line Wrapping

When saving XML documents, Mini-XML normally wraps output lines at column 75 so that the text is readable in terminal windows. The `mxmlSetWrapMargin` function overrides the default wrap margin:

        /* Set the margin to 132 columns */
        mxmlSetWrapMargin(132);

        /* Disable wrapping */
        mxmlSetWrapMargin(0);

## Finding and Iterating Nodes

The `mxmlWalkPrev` and `mxmlWalkNext`functions can be used to iterate through the XML node tree:

        mxml_node_t *node;

        node = mxmlWalkPrev(current, tree,
                            MXML_DESCEND);

        node = mxmlWalkNext(current, tree,
                            MXML_DESCEND);

In addition, you can find a named element/node using the `mxmlFindElement` function:

        mxml_node_t *node;

        node = mxmlFindElement(tree, tree, "name",
                               "attr", "value",
                               MXML_DESCEND);

The `name`, `attr`, and `value` arguments can be passed as `NULL` to act as wildcards, e.g.:

        /* Find the first "a" element */
        node = mxmlFindElement(tree, tree, "a",
                               NULL, NULL,
                               MXML_DESCEND);

        /* Find the first "a" element with "href"
           attribute */
        node = mxmlFindElement(tree, tree, "a",
                               "href", NULL,
                               MXML_DESCEND);

        /* Find the first "a" element with "href"
           to a URL */
        node = mxmlFindElement(tree, tree, "a",
                               "href",
                               "http://www.easysw.com/",
                               MXML_DESCEND);

        /* Find the first element with a "src"
           attribute */
        node = mxmlFindElement(tree, tree, NULL,
                               "src", NULL,
                               MXML_DESCEND);

        /* Find the first element with a "src"
           = "foo.jpg" */
        node = mxmlFindElement(tree, tree, NULL,
                               "src", "foo.jpg",
                               MXML_DESCEND);

You can also iterate with the same function:

        mxml_node_t *node;

        for (node = mxmlFindElement(tree, tree,
                                    "name",
                                    NULL, NULL,
                                    MXML_DESCEND);
             node != NULL;
             node = mxmlFindElement(node, tree,
                                    "name",
                                    NULL, NULL,
                                    MXML_DESCEND))
        {
          ... do something ...
        }

The `MXML_DESCEND` argument can actually be one of three constants:

- `MXML_NO_DESCEND` means to not to look at any child nodes in the element hierarchy, just look at siblings at the same level or parent nodes until the top node or top-of-tree is reached.

  The previous node from "group" would be the "node" element to the left, while the next node from "group" would be the "node" element to the right.

- `MXML_DESCEND_FIRST` means that it is OK to descend to the first child of a node, but not to descend further when searching. You'll normally use this when iterating through direct children of a parent node, e.g. all of the "node" and "group" elements under the "?xml" parent node in the example above.

  This mode is only applicable to the search function; the walk functions treat this as `MXML_DESCEND` since every call is a first time.

- `MXML_DESCEND` means to keep descending until you hit the bottom of the tree. The previous node from "group" would be the "val3" node and the next node would be the first node element under "group".

  If you were to walk from the root node "?xml" to the end of the tree with `mxmlWalkNext()`, the order would be:

  `?xml data node val1 node val2 node val3 group node val4 node val5 node val6 node val7 node val8`

  If you started at "val8" and walked using `mxmlWalkPrev()`, the order would be reversed, ending at "?xml".

# More Mini-XML Programming Techniques

This chapter shows additional ways to use the Mini-XML library in your programs.

## Load Callbacks

Chapter 2 introduced the `mxmlLoadFile()` and `mxmlLoadString()` functions. The last argument to these functions is a callback function which is used to determine the value type of each data node in an XML document.

Mini-XML defines several standard callbacks for simple XML data files:

- `MXML_INTEGER_CALLBACK` - All data nodes contain whitespace-separated integers.
- `MXML_OPAQUE_CALLBACK` - All data nodes contain opaque strings ("CDATA").
- `MXML_REAL_CALLBACK` - All data nodes contain whitespace-separated floating-point numbers.
- `MXML_TEXT_CALLBACK` - All data nodes contain whitespace-separated strings.

You can provide your own callback functions for more complex XML documents. Your callback function will receive a pointer to the current element node and must return the value type of the immediate children for that element node: `MXML_INTEGER`, `MXML_OPAQUE`, `MXML_REAL`, or `MXML_TEXT`. The function is called after the element and its attributes have been read, so you can look at the element name, attributes, and attribute values to determine the proper value type to return.

The following callback function looks for an attribute named "type" or the element name to determine the value type for its child nodes:

        mxml_type_t
        type_cb(mxml_node_t *node)
        {
          const char *type;

         /*
          * You can lookup attributes and/or use the
          * element name, hierarchy, etc...
          */

          type = mxmlElementGetAttr(node, "type");
          if (type == NULL)
    	type = node->value.element.name;

          if (!strcmp(type, "integer"))
    	return (MXML_INTEGER);
          else if (!strcmp(type, "opaque"))
    	return (MXML_OPAQUE);
          else if (!strcmp(type, "real"))
    	return (MXML_REAL);
          else
    	return (MXML_TEXT);
        }

To use this callback function, simply use the name when you call any of the load functions:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "r");
        tree = mxmlLoadFile(NULL, fp, type_cb);
        fclose(fp);

## Save Callbacks

Chapter 2 also introduced the `mxmlSaveFile()`, `mxmlSaveString()`, and `mxmlSaveAllocString()` functions. The last argument to these functions is a callback function which is used to automatically insert whitespace in an XML document.

Your callback function will be called up to four times for each element node with a pointer to the node and a "where" value of `MXML_WS_BEFORE_OPEN`, `MXML_WS_AFTER_OPEN`, `MXML_WS_BEFORE_CLOSE`, or `MXML_WS_AFTER_CLOSE`. The callback function should return `NULL` if no whitespace should be added and the string to insert (spaces, tabs, carriage returns, and newlines) otherwise.

The following whitespace callback can be used to add whitespace to XHTML output to make it more readable in a standard text editor:

        const char *
        whitespace_cb(mxml_node_t *node,
                      int where)
        {
          const char *name;

         /*
          * We can conditionally break to a new line
          * before or after any element. These are
          * just common HTML elements...
          */

          name = node->value.element.name;

          if (!strcmp(name, "html") ||
              !strcmp(name, "head") ||
              !strcmp(name, "body") ||
    	  !strcmp(name, "pre") ||
              !strcmp(name, "p") ||
    	  !strcmp(name, "h1") ||
              !strcmp(name, "h2") ||
              !strcmp(name, "h3") ||
    	  !strcmp(name, "h4") ||
              !strcmp(name, "h5") ||
              !strcmp(name, "h6"))
          {
           /*
    	* Newlines before open and after
            * close...
    	*/

    	if (where == MXML_WS_BEFORE_OPEN ||
                where == MXML_WS_AFTER_CLOSE)
    	  return ("\n");
          }
          else if (!strcmp(name, "dl") ||
                   !strcmp(name, "ol") ||
                   !strcmp(name, "ul"))
          {
           /*
    	* Put a newline before and after list
            * elements...
    	*/

    	return ("\n");
          }
          else if (!strcmp(name, "dd") ||
                   !strcmp(name, "dt") ||
                   !strcmp(name, "li"))
          {
           /*
    	* Put a tab before <li>'s, * <dd>'s,
            * and <dt>'s, and a newline after them...
    	*/

    	if (where == MXML_WS_BEFORE_OPEN)
    	  return ("\t");
    	else if (where == MXML_WS_AFTER_CLOSE)
    	  return ("\n");
          }

         /*
          * Return NULL for no added whitespace...
          */

          return (NULL);
        }

To use this callback function, simply use the name when you call any of the save functions:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "w");
        mxmlSaveFile(tree, fp, whitespace_cb);
        fclose(fp);

## Custom Data Types

Mini-XML supports custom data types via global load and save callbacks. Only a single set of callbacks can be active at any time, however your callbacks can store additional information in order to support multiple custom data types as needed. The `MXML_CUSTOM` node type identifies custom data nodes.

The load callback receives a pointer to the current data node and a string of opaque character data from the XML source with character entities converted to the corresponding UTF-8 characters. For example, if we wanted to support a custom date/time type whose value is encoded as "yyyy-mm-ddThh:mm:ssZ" (ISO format), the load callback would look like the following:

        typedef struct
        {
          unsigned      year,    /* Year */
                        month,   /* Month */
                        day,     /* Day */
                        hour,    /* Hour */
                        minute,  /* Minute */
                        second;  /* Second */
          time_t        unix;    /* UNIX time */
        } iso_date_time_t;

        int
        load_custom(mxml_node_t *node,
                    const char *data)
        {
          iso_date_time_t *dt;
          struct tm tmdata;

         /*
          * Allocate data structure...
          */

          dt = calloc(1, sizeof(iso_date_time_t));

         /*
          * Try reading 6 unsigned integers from the
          * data string...
          */

          if (sscanf(data, "%u-%u-%uT%u:%u:%uZ",
                     &(dt->year), &(dt->month),
                     &(dt->day), &(dt->hour),
                     &(dt->minute),
                     &(dt->second)) != 6)
          {
           /*
            * Unable to read numbers, free the data
            * structure and return an error...
            */

            free(dt);

            return (-1);
          }

         /*
          * Range check values...
          */

          if (dt->month <1 || dt->month > 12 ||
              dt->day  <1 || dt->day > 31 ||
              dt->hour  <0 || dt->hour > 23 ||
              dt->minute  <0 || dt->minute > 59 ||
              dt->second  <0 || dt->second > 59)
          {
           /*
            * Date information is out of range...
            */

            free(dt);

            return (-1);
          }

         /*
          * Convert ISO time to UNIX time in
          * seconds...
          */

          tmdata.tm_year = dt->year - 1900;
          tmdata.tm_mon  = dt->month - 1;
          tmdata.tm_day  = dt->day;
          tmdata.tm_hour = dt->hour;
          tmdata.tm_min  = dt->minute;
          tmdata.tm_sec  = dt->second;

          dt->unix = gmtime(&tmdata);

         /*
          * Assign custom node data and destroy
          * function pointers...
          */

          node->value.custom.data    = dt;
          node->value.custom.destroy = free;

         /*
          * Return with no errors...
          */

          return (0);
        }

The function itself can return 0 on success or -1 if it is unable to decode the custom data or the data contains an error. Custom data nodes contain a `void` pointer to the allocated custom data for the node and a pointer to a destructor function which will free the custom data when the node is deleted.

The save callback receives the node pointer and returns an allocated string containing the custom data value. The following save callback could be used for our ISO date/time type:

        char *
        save_custom(mxml_node_t *node)
        {
          char data[255];
          iso_date_time_t *dt;

          dt = (iso_date_time_t *)node->custom.data;

          snprintf(data, sizeof(data),
                   "%04u-%02u-%02uT%02u:%02u:%02uZ",
                   dt->year, dt->month, dt->day,
                   dt->hour, dt->minute, dt->second);

          return (strdup(data));
        }

You register the callback functions using the `mxmlSetCustomHandlers()` function:

        mxmlSetCustomHandlers(load_custom,
                              save_custom);

## Changing Node Values

All of the examples so far have concentrated on creating and loading new XML data nodes. Many applications, however, need to manipulate or change the nodes during their operation, so Mini-XML provides functions to change node values safely and without leaking memory.

Existing nodes can be changed using the `mxmlSetElement()`, `mxmlSetInteger()`, `mxmlSetOpaque()` , `mxmlSetReal()`, `mxmlSetText()`, and `mxmlSetTextf()` functions. For example, use the following function call to change a text node to contain the text "new" with leading whitespace:

        mxml_node_t *node;

        mxmlSetText(node, 1, "new");

## Formatted Text

The `mxmlNewTextf()` and `mxmlSetTextf()` functions create and change text nodes, respectively, using `printf`-style format strings and arguments. For example, use the following function call to create a new text node containing a constructed filename:

        mxml_node_t *node;

        node = mxmlNewTextf(node, 1, "%s/%s",
                            path, filename);

## Indexing

Mini-XML provides functions for managing indices of nodes. The current implementation provides the same functionality as `mxmlFindElement()`. The advantage of using an index is that searching and enumeration of elements is significantly faster. The only disadvantage is that each index is a static snapshot of the XML document, so indices are not well suited to XML data that is updated more often than it is searched. The overhead of creating an index is approximately equal to walking the XML document tree. Nodes in the index are sorted by element name and attribute value.

Indices are stored in `mxml_index_t` structures. The `mxmlIndexNew()` function creates a new index:

        mxml_node_t *tree;
        mxml_index_t *ind;

        ind = mxmlIndexNew(tree, "element",
                           "attribute");

The first argument is the XML node tree to index. Normally this will be a pointer to the `?xml` element.

The second argument contains the element to index; passing `NULL` indexes all element nodes alphabetically.

The third argument contains the attribute to index; passing `NULL` causes only the element name to be indexed.

Once the index is created, the `mxmlIndexEnum()`, `mxmlIndexFind()` , and `mxmlIndexReset()` functions are used to access the nodes in the index. The `mxmlIndexReset()` function resets the "current" node pointer in the index, allowing you to do new searches and enumerations on the same index. Typically you will call this function prior to your calls to `mxmlIndexEnum()` and `mxmlIndexFind()`.

The `mxmlIndexEnum()` function enumerates each of the nodes in the index and can be used in a loop as follows:

        mxml_node_t *node;

        mxmlIndexReset(ind);

        while ((node = mxmlIndexEnum(ind)) != NULL)
        {
          // do something with node
        }

The `mxmlIndexFind()` function locates the next occurrence of the named element and attribute value in the index. It can be used to find all matching elements in an index, as follows:

        mxml_node_t *node;

        mxmlIndexReset(ind);

        while ((node = mxmlIndexFind(ind, "element",
                                     "attr-value"))
                    != NULL)
        {
          // do something with node
        }

The second and third arguments represent the element name and attribute value, respectively. A `NULL` pointer is used to return all elements or attributes in the index. Passing `NULL` for both the element name and attribute value is equivalent to calling `mxmlIndexEnum`.

When you are done using the index, delete it using the `mxmlIndexDelete()` function:

        mxmlIndexDelete(ind);

## SAX (Stream) Loading of Documents

Mini-XML supports an implementation of the Simple API for XML (SAX) which allows you to load and process an XML document as a stream of nodes. Aside from allowing you to process XML documents of any size, the Mini-XML implementation also allows you to retain portions of the document in memory for later processing.

The `mxmlSAXLoadFd`, `mxmlSAXLoadFile`, and `mxmlSAXLoadString` functions provide the SAX loading APIs. Each function works like the corresponding `mxmlLoad` function but uses a callback to process each node as it is read.

The callback function receives the node, an event code, and a user data pointer you supply:

        void
        sax_cb(mxml_node_t *node,
               mxml_sax_event_t event,
               void *data)
        {
          ... do something ...
        }

The event will be one of the following:

- `MXML_SAX_CDATA` - CDATA was just read
- `MXML_SAX_COMMENT` - A comment was just read
- `MXML_SAX_DATA` - Data (custom, integer, opaque, real, or text) was just read
- `MXML_SAX_DIRECTIVE` - A processing directive was just read
- `MXML_SAX_ELEMENT_CLOSE` - An open element was just read (`<element>`)
- `MXML_SAX_ELEMENT_OPEN` - A close element was just read (`</element>`)

Elements are released after the close element is processed. All other nodes are released after they are processed. The SAX callback can retain the node using the `mxmlRetain` function. For example, the following SAX callback will retain all nodes, effectively simulating a normal in-memory load:

        void
        sax_cb(mxml_node_t *node,
               mxml_sax_event_t event,
               void *data)
        {
          if (event != MXML_SAX_ELEMENT_CLOSE)
            mxmlRetain(node);
        }

More typically the SAX callback will only retain a small portion of the document that is needed for post-processing. For example, the following SAX callback will retain the title and headings in an XHTML file. It also retains the (parent) elements like `<html>`, `<head>`, and `<body>`, and processing directives like `<?xml ... ?>` and `<!DOCTYPE ... >`:

        void
        sax_cb(mxml_node_t *node,
               mxml_sax_event_t event,
               void *data)
        {
          if (event == MXML_SAX_ELEMENT_OPEN)
          {
           /*
            * Retain headings and titles...
            */

            char *name = node->value.element.name;

            if (!strcmp(name, "html") ||
                !strcmp(name, "head") ||
                !strcmp(name, "title") ||
                !strcmp(name, "body") ||
                !strcmp(name, "h1") ||
                !strcmp(name, "h2") ||
                !strcmp(name, "h3") ||
                !strcmp(name, "h4") ||
                !strcmp(name, "h5") ||
                !strcmp(name, "h6"))
              mxmlRetain(node);
          }
          else if (event == MXML_SAX_DIRECTIVE)
            mxmlRetain(node);
          else if (event == MXML_SAX_DATA &&
                   node->parent->ref_count > 1)
          {
           /*
            * If the parent was retained, then retain
            * this data node as well.
            */

            mxmlRetain(node);
          }
        }

The resulting skeleton document tree can then be searched just like one loaded using the `mxmlLoad` functions. For example, a filter that reads an XHTML document from stdin and then shows the title and headings in the document would look like:

        mxml_node_t *doc, *title, *body, *heading;

        doc = mxmlSAXLoadFd(NULL, 0,
                            MXML_TEXT_CALLBACK,
                            sax_cb, NULL);

        title = mxmlFindElement(doc, doc, "title",
                                NULL, NULL,
                                MXML_DESCEND);

        if (title)
          print_children(title);

        body = mxmlFindElement(doc, doc, "body",
                               NULL, NULL,
                               MXML_DESCEND);

        if (body)
        {
          for (heading = body->child;
               heading;
               heading = heading->next)
            print_children(heading);
        }

# Using the mxmldoc Utility

This chapter describes how to use `mxmldoc(1)` program to automatically generate documentation from C and C++ source files.

## The Basics

Originally developed to generate the Mini-XML and CUPS API documentation, `mxmldoc` is now a general-purpose utility which scans C and C++ source files to produce HTML and man page documentation along with an XML file representing the functions, types, and definitions in those source files. Unlike popular documentation generators like Doxygen or Javadoc, `mxmldoc` uses in-line comments rather than comment headers, allowing for more "natural" code documentation.

By default, `mxmldoc` produces HTML documentation. For example, the following command will scan all of the C source and header files in the current directory and produce a HTML documentation file called filename.html:

        mxmldoc *.h *.c >filename.html ENTER

You can also specify an XML file to create which contains all of the information from the source files. For example, the following command creates an XML file called filename.xml in addition to the HTML file:

        mxmldoc filename.xml *.h *.c >filename.html ENTER

The `--no-output` option disables the normal HTML output:

        mxmldoc --no-output filename.xml *.h *.c ENTER

You can then run `mxmldoc` again with the XML file alone to generate the HTML documentation:

        mxmldoc filename.xml >filename.html ENTER

The `--man filename` option tells `mxmldoc` to create a man page instead of HTML documentation, for example:

        mxmldoc --man filename filename.xml \
            >filename.man ENTER

        mxmldoc --man filename *.h *.c \
            >filename.man ENTER

        mxmldoc --man filename filename.xml *.h *.c \
            >filename.man ENTER

## Commenting Your Code

As noted previously, `mxmldoc` looks for in-line comments to describe the functions, types, and constants in your code. `Mxmldoc` will document all public names it finds in your source files - any names starting with the underscore character (_) or names that are documented with the @private@ directive are treated as private and are undocumented.

Comments appearing directly before a function or type definition are used to document that function or type. Comments appearing after argument, definition, return type, or variable declarations are used to document that argument, definition, return type, or variable. For example, the following code excerpt defines a key/value structure and a function that creates a new instance of that structure:

        /* A key/value pair. This is used with the
           dictionary structure. */

        struct keyval
        {
          char *key; /* Key string */
          char *val; /* Value string */
        };

        /* Create a new key/value pair. */

        struct keyval * /* New key/value pair */
        new_keyval(
            const char *key, /* Key string */
    	const char *val) /* Value string */
        {
          ...
        }

`Mxmldoc` also knows to remove extra asterisks (*) from the comment string, so the comment string:

        /*
         * Compute the value of PI.
         *
         * The function connects to an Internet server
         * that streams audio of mathematical monks
         * chanting the first 100 digits of PI.
         */

will be shown as:

        Compute the value of PI.

        The function connects to an Internet server
        that streams audio of mathematical monks
        chanting the first 100 digits of PI.

Comments can also include the following special `@name ...@` directive strings:

- `@deprecated@` - flags the item as deprecated to discourage its use
- `@private@` - flags the item as private so it will not be included in the documentation
- `@since ...@` - flags the item as new since a particular release. The text following the `@since` up to the closing `@` is highlighted in the generated documentation, e.g. `@since CUPS 1.3@`.

## Titles, Sections, and Introductions

`Mxmldoc` also provides options to set the title, section, and introduction text for the generated documentation. The `--title text` option specifies the title for the documentation. The title string is usually put in quotes:

        mxmldoc filename.xml \
            --title "My Famous Documentation" \
            >filename.html ENTER

The `--section name` option specifies the section for the documentation. For HTML documentation, the name is placed in a HTML comment such as:

        <!-- SECTION: name -->

For man pages, the section name is usually just a number ("3"), or a number followed by a vendor name ("3acme"). The section name is used in the `.TH` directive in the man page:

        .TH mylibrary 3acme "My Title" ...

The default section name for man page output is "3". There is no default section name for HTML output.

Finally, the `--intro filename` option specifies a file to embed after the title and section but before the generated documentation. For HTML documentation, the file must consist of valid HTML without the usual `DOCTYPE`, `html`, and `body` elements. For man page documentation, the file must consist of valid `nroff(1)` text.

# Mini-XML License

The Mini-XML library and included programs are provided under the terms of the GNU Library General Public License (LGPL) with the following exceptions:

1. Static linking of applications to the Mini-XML library does not constitute a derivative work and does not require the author to provide source code for the application, use the shared Mini-XML libraries, or link their applications against a user-supplied version of Mini-XML.

   If you link the application to a modified version of Mini-XML, then the changes to Mini-XML must be provided under the terms of the LGPL in sections 1, 2, and 4.

2. You do not have to provide a copy of the Mini-XML license with programs that are linked to the Mini-XML library, nor do you have to identify the Mini-XML license in your program or documentation as required by section 6 of the LGPL.

GNU LIBRARY GENERAL PUBLIC LICENSE

Version 2, June 1991
Copyright (C) 1991 Free Software Foundation, Inc.
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
[This is the first released version of the library GPL. It is numbered 2 because it goes with version 2 of the ordinary GPL.]

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one line to give the library's name and an idea of what it does.
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Also add information on how to contact you by electronic and paper mail.

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signature of Ty Coon, 1 April 1990 Ty Coon, President of Vice

That's all there is to it!

# Release Notes

## Changes in Mini-XML 2.5

- The mxmldoc program now makes greater use of CSS and supports a --css option to embed an alternate stylesheet.
- The mxmldoc program now supports --header and --footer options to insert documentation content before and after the generated content.
- The mxmldoc program now supports a --framed option to generate framed HTML output.
- The mxmldoc program now creates a table of contents including any headings in the --intro file when generating HTML output.
- The man pages and man page output from mxmldoc did not use "\-" for dashes (STR #68)
- The debug version of the Mini-XML DLL could not be built (STR #65)
- Processing instructions and directives did not work when not at the top level of a document (STR #67)
- Spaces around the "=" in attributes were not supported (STR #67)

## Changes in Mini-XML 2.4

- Fixed shared library build problems on HP-UX and Mac OS X.
- The mxmldoc program did not output argument descriptions for functions properly.
- All global settings (custom, error, and entity callbacks and the wrap margin) are now managed separately for each thread.
- Added mxmlElementDeleteAttr() function (STR #59)
- mxmlElementSetAttrf() did not work (STR #57)
- mxmlLoad*() incorrectly treated declarations as parent elements (STR #56)
- mxmlLoad*() incorrectly allowed attributes without values (STR #47)
- Fixed Visual C++ build problems (STR #49)
- mxmlLoad*() did not return NULL when an element contained an error (STR #46)
- Added support for the apos character entity (STR #54)
- Fixed whitespace detection with Unicode characters (STR #48)
- mxmlWalkNext() and mxmlWalkPrev() did not work correctly when called with a node with no children as the top node (STR #53)

## Changes in Mini-XML 2.3

- Added two exceptions to the LGPL to support static linking of applications against Mini-XML
- The mxmldoc utility can now generate man pages, too.
- Added a mxmlNewXML() function
- Added a mxmlElementSetAttrf() function (STR #43)
- Added a snprintf() emulation function for the test program (STR #32)
- Added the _CRT_SECURE_NO_DEPRECATE definition when building on VC++ 2005 (STR #36)
- mxmlLoad*() did not detect missing > characters in elements (STR #41)
- mxmlLoad*() did not detect missing close tags at the end of an XML document (STR #45)
- Added user_data and ref_count members to mxml_node_t structure
- Added mxmlReleaseNode() and mxmlRetainNode() APIs for reference-counted nodes
- Added mxmlSetWrapMargin() to control the wrapping of XML output
- Added conditional check for EINTR error code for certain Windows compilers that do not define it (STR #33)
- The mxmldoc program now generates correct HTML 4.0 output - previously it generated invalid XHTML
- The mxmldoc program now supports "@deprecated@, "@private@", and "@since version@" comments
- Fixed function and enumeration type bugs in mxmldoc
- Fixed the XML schema for mxmldoc
- The mxmldoc program now supports --intro, --section, and --title options
- The mxmlLoad*() functions could leak a node on an error (STR #27)
- The mxml_vsnprintf() function could get in an infinite loop on a buffer overflow (STR #25)
- Added new mxmlNewCDATA() and mxmlSetCDATA() functions to create and set CDATA nodes, which are really just special element nodes
- Added new MXML_IGNORE type and MXML_IGNORE_CB callback to ignore non-element nodes, e.g. whitespace
- mxmlLoad*() did not treat custom data as opaque, so whitespace characters would be lost

## Changes in Mini-XML 2.2.2

- mxmlLoad*() did not treat custom data as opaque, so whitespace characters would be lost.

## Changes in Mini-XML 2.2.1

- mxmlLoadFd(), mxmlLoadFile(), and mxmlLoadString() now correctly return NULL on error (STR #21)
- mxmlNewInteger(), mxmlNewOpaque(), mxmlNewReal(), mxmlNewText(), and mxmlNewTextf() incorrectly required a parent node (STR #22)
- Fixed an XML output bug in mxmldoc.
- The "make install" target now uses the install command to set the proper permissions on UNIX/Linux/OSX.
- Fixed a MingW/Cygwin compilation problem (STR #18)

## Changes in Mini-XML 2.2

- Added shared library support (STR #17)
- mxmlLoad*() now returns an error when an XML stream contains illegal control characters (STR #10)
- mxmlLoad*() now returns an error when an element contains two attributes with the same name in conformance with the XML spec (STR #16)
- Added support for CDATA (STR #14, STR #15)
- Updated comment and processing instruction handling - no entity support per XML specification.
- Added checking for invalid comment termination ("--->" is not allowed)

## Changes in Mini-XML 2.1

- Added support for custom data nodes (STR #6)
- Now treat UTF-8 sequences which are longer than necessary as an error (STR #4)
- Fixed entity number support (STR #8)
- Fixed mxmlLoadString() bug with UTF-8 (STR #7)
- Fixed entity lookup bug (STR #5)
- Added mxmlLoadFd() and mxmlSaveFd() functions.
- Fixed multi-word UTF-16 handling.

## Changes in Mini-XML 2.0

- New programmers manual.
- Added Visual C++ project files for Microsoft Windows users.
- Added optimizations to mxmldoc, mxmlSaveFile(), and mxmlIndexNew() (STR #2)
- mxmlEntityAddCallback() now returns an integer status (STR #2)
- Added UTF-16 support (input only; all output is UTF-8)
- Added index functions to build a searchable index of XML nodes.
- Added character entity callback interface to support additional character entities beyond those defined in the XHTML specification.
- Added support for XHTML character entities.
- The mxmldoc utility now produces XML output which conforms to an updated XML schema, described in the file "doc/mxmldoc.xsd".
- Changed the whitespace callback interface to return strings instead of a single character, allowing for greater control over the formatting of XML files written using Mini-XML. THIS CHANGE WILL REQUIRE CHANGES TO YOUR 1.x CODE IF YOU USE WHITESPACE CALLBACKS.
- The mxmldoc utility now produces XML output which conforms to an updated XML schema, described in the file "doc/mxmldoc.xsd".
- Changed the whitespace callback interface to return strings instead of a single character, allowing for greater control over the formatting of XML files written using Mini-XML. THIS CHANGE WILL REQUIRE CHANGES TO YOUR 1.x CODE IF YOU USE WHITESPACE CALLBACKS.
- The mxmldoc utility is now capable of documenting C++ classes, functions, and structures, and correctly handles C++ comments.
- Added new modular tests for mxmldoc.
- Updated the mxmldoc output to be more compatible with embedding in manuals produced with HTMLDOC.
- The makefile incorrectly included a "/" separator between the destination path and install path. This caused problems when building and installing with MingW.

## Changes in Mini-XML 1.3

- Fixes for mxmldoc.
- Added support for reading standard HTML entity names.
- mxmlLoadString/File() did not decode character entities in element names, attribute names, or attribute values.
- mxmlLoadString/File() would crash when loading non- conformant XML data under an existing parent (top) node.
- Fixed several bugs in the mxmldoc utility.
- Added new error callback function to catch a variety of errors and log them to someplace other than stderr.
- The mxmlElementSetAttr() function now allows for NULL attribute values.
- The load and save functions now properly handle quoted element and attribute name strings properly, e.g. for !DOCTYPE declarations.

## Changes in Mini-XML 1.2

- Added new "set" methods to set the value of a node.
- Added new formatted text methods mxmlNewTextf() and mxmlSetTextf() to create/set a text node value using printf-style formats.
- Added new standard callbacks for use with the mxmlLoad functions.
- Updated the HTML documentation to include examples of the walk and load function output.
- Added --with/without-ansi configure option to control the strdup() function check.
- Added --with/without-snprintf configure option to control the snprintf() and vsnprintf() function checks.

## Changes in Mini-XML 1.1.2

- The mxml(3) man page wasn't updated for the string functions.
- mxmlSaveString() returned the wrong number of characters.
- mxml_add_char() updated the buffer pointer in the wrong place.

## Changes in Mini-XML 1.1.1

- The private mxml_add_ch() function did not update the start-of-buffer pointer which could cause a crash when using mxmlSaveString().
- The private mxml_write_ws() function called putc() instead of using the proper callback which could cause a crash when using mxmlSaveString().
- Added a mxmlSaveAllocString() convenience function for saving an XML node tree to an allocated string.

## Changes in Mini-XML 1.1

- The mxmlLoadFile() function now uses dynamically allocated string buffers for element names, attribute names, and attribute values. Previously they were capped at 16383, 255, and 255 bytes, respectively.
- Added a new mxmlLoadString() function for loading an XML node tree from a string.
- Added a new mxmlSaveString() function for saving an XML node tree to a string.
- Add emulation of strdup() if the local platform does not provide the function.

## Changes in Mini-XML 1.0

- The mxmldoc program now handles function arguments, structures, unions, enumerations, classes, and typedefs properly.
- Documentation provided via mxmldoc and more in-line comments in the code.
- Added man pages and packaging files.

## Changes in Mini-XML 0.93

- New mxmldoc example program that is also used to create and update code documentation using XML and produce HTML reference pages.
- Added mxmlAdd() and mxmlRemove() functions to add and remove nodes from a tree. This provides more flexibility over where the nodes are inserted and allows nodes to be moved within the tree as needed.
- mxmlLoadFile() now correctly handles comments.
- mxmlLoadFile() now supports the required "gt", "quot", and "nbsp" character entities.
- mxmlSaveFile() now uses newlines as whitespace when valid to do so.
- mxmlFindElement() now also takes attribute name and attribute value string arguments to limit the search to specific elements with attributes and/or values.
NULL pointers can be used as "wildcards".
- Added uninstall target to makefile, and auto-reconfig if Makefile.in or configure.in are changed.
- mxmlFindElement(), mxmlWalkNext(), and mxmlWalkPrev() now all provide "descend" arguments to control whether they descend into child nodes in the tree.
- Fixed some whitespace issues in mxmlLoadFile().
- Fixed Unicode output and whitespace issues in mxmlSaveFile().
- mxmlSaveFile() now supports a whitespace callback to provide more human-readable XML output under program control.

## Changes in Mini-XML 0.92

- mxmlSaveFile() didn't return a value on success.

## Changes in Mini-XML 0.91

- mxmlWalkNext() would go into an infinite loop.

## Changes in Mini-XML 0.9

- Initial public release.

# Library Reference

## Contents

- Functions
  - mxmlAdd
  - mxmlDelete
  - mxmlElementDeleteAttr
  - mxmlElementGetAttr
  - mxmlElementSetAttr
  - mxmlElementSetAttrf
  - mxmlEntityAddCallback
  - mxmlEntityGetName
  - mxmlEntityGetValue
  - mxmlEntityRemoveCallback
  - mxmlFindElement
  - mxmlIndexDelete
  - mxmlIndexEnum
  - mxmlIndexFind
  - mxmlIndexNew
  - mxmlIndexReset
  - mxmlLoadFd
  - mxmlLoadFile
  - mxmlLoadString
  - mxmlNewCDATA
  - mxmlNewCustom
  - mxmlNewElement
  - mxmlNewInteger
  - mxmlNewOpaque
  - mxmlNewReal
  - mxmlNewText
  - mxmlNewTextf
  - mxmlNewXML
  - mxmlRelease
  - mxmlRemove
  - mxmlRetain
  - mxmlSAXLoadFd
  - mxmlSAXLoadFile
  - mxmlSAXLoadString
  - mxmlSaveAllocString
  - mxmlSaveFd
  - mxmlSaveFile
  - mxmlSaveString
  - mxmlSetCDATA
  - mxmlSetCustom
  - mxmlSetCustomHandlers
  - mxmlSetElement
  - mxmlSetErrorCallback
  - mxmlSetInteger
  - mxmlSetOpaque
  - mxmlSetReal
  - mxmlSetText
  - mxmlSetTextf
  - mxmlSetWrapMargin
  - mxmlWalkNext
  - mxmlWalkPrev
- Data Types
  - mxml_attr_t
  - mxml_custom_destroy_cb_t
  - mxml_custom_load_cb_t
  - mxml_custom_save_cb_t
  - mxml_custom_t
  - mxml_element_t
  - mxml_error_cb_t
  - mxml_index_t
  - mxml_load_cb_t
  - mxml_node_t
  - mxml_save_cb_t
  - mxml_sax_cb_t
  - mxml_sax_event_t
  - mxml_text_t
  - mxml_value_t
- Structures
  - mxml_attr_s
  - mxml_custom_s
  - mxml_element_s
  - mxml_index_s
  - mxml_node_s
  - mxml_text_s
- Unions
  - mxml_value_u
- Constants
  - mxml_sax_event_e
  - mxml_type_e

## Functions

### mxmlAdd

Add a node to a tree.

void mxmlAdd (
mxml_node_t *parent,
int where,
mxml_node_t *child,
mxml_node_t *node
);

#### Parameters

parent
  Parent node
where
  Where to add, MXML_ADD_BEFORE or MXML_ADD_AFTER
child
  Child node for where or MXML_ADD_TO_PARENT
node
  Node to add

#### Discussion

Adds the specified node to the parent. If the child argument is not NULL, puts the new node before or after the specified child depending on the value of the where argument. If the child argument is NULL, puts the new node at the beginning of the child list (MXML_ADD_BEFORE) or at the end of the child list (MXML_ADD_AFTER). The constant MXML_ADD_TO_PARENT can be used to specify a NULL child pointer.

### mxmlDelete

Delete a node and all of its children.

void mxmlDelete (
mxml_node_t *node
);

#### Parameters

node
  Node to delete

#### Discussion

If the specified node has a parent, this function first removes the node from its parent using the mxmlRemove() function.

### Mini-XML 2.4 mxmlElementDeleteAttr

Delete an attribute.

void mxmlElementDeleteAttr (
mxml_node_t *node,
const char *name
);

#### Parameters

node
  Element
name
  Attribute name

### mxmlElementGetAttr

Get an attribute.

const char *mxmlElementGetAttr (
mxml_node_t *node,
const char *name
);

#### Parameters

node
  Element node
name
  Name of attribute

#### Return Value

Attribute value or NULL

#### Discussion

This function returns NULL if the node is not an element or the named attribute does not exist.

### mxmlElementSetAttr

Set an attribute.

void mxmlElementSetAttr (
mxml_node_t *node,
const char *name,
const char *value
);

#### Parameters

node
  Element node
name
  Name of attribute
value
  Attribute value

#### Discussion

If the named attribute already exists, the value of the attribute is replaced by the new string value. The string value is copied into the element node. This function does nothing if the node is not an element.

### Mini-XML 2.3 mxmlElementSetAttrf

Set an attribute with a formatted value.

void mxmlElementSetAttrf (
mxml_node_t *node,
const char *name,
const char *format,
...
);

#### Parameters

node
  Element node
name
  Name of attribute
format
  Printf-style attribute value
...
  Additional arguments as needed

#### Discussion

If the named attribute already exists, the value of the attribute is replaced by the new formatted string. The formatted string value is copied into the element node. This function does nothing if the node is not an element.

### mxmlEntityAddCallback

Add a callback to convert entities to Unicode.

int mxmlEntityAddCallback (void);

#### Return Value

0 on success, -1 on failure

### mxmlEntityGetName

Get the name that corresponds to the character value.

const char *mxmlEntityGetName (
int val
);

#### Parameters

val
  Character value

#### Return Value

Entity name or NULL

#### Discussion

If val does not need to be represented by a named entity, NULL is returned.

### mxmlEntityGetValue

Get the character corresponding to a named entity.

int mxmlEntityGetValue (
const char *name
);

#### Parameters

name
  Entity name

#### Return Value

Character value or -1 on error

#### Discussion

The entity name can also be a numeric constant. -1 is returned if the name is not known.

### mxmlEntityRemoveCallback

Remove a callback.

void mxmlEntityRemoveCallback (void);

### mxmlFindElement

Find the named element.

mxml_node_t *mxmlFindElement (
mxml_node_t *node,
mxml_node_t *top,
const char *name,
const char *attr,
const char *value,
int descend
);

#### Parameters

node
  Current node
top
  Top node
name
  Element name or NULL for any
attr
  Attribute name, or NULL for none
value
  Attribute value, or NULL for any
descend
  Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Return Value

Element node or NULL

#### Discussion

The search is constrained by the name, attribute name, and value; any NULL names or values are treated as wildcards, so different kinds of searches can be implemented by looking for all elements of a given name or all elements with a specific attribute. The descend argument determines whether the search descends into child nodes; normally you will use MXML_DESCEND_FIRST for the initial search and MXML_NO_DESCEND to find additional direct descendents of the node. The top node argument constrains the search to a particular node's children.

### mxmlIndexDelete

Delete an index.

void mxmlIndexDelete (
mxml_index_t *ind
);

#### Parameters

ind
  Index to delete

### mxmlIndexEnum

Return the next node in the index.

mxml_node_t *mxmlIndexEnum (
mxml_index_t *ind
);

#### Parameters

ind
  Index to enumerate

#### Return Value

Next node or NULL if there is none

#### Discussion

Nodes are returned in the sorted order of the index.

### mxmlIndexFind

Find the next matching node.

mxml_node_t *mxmlIndexFind (
mxml_index_t *ind,
const char *element,
const char *value
);

#### Parameters

ind
  Index to search
element
  Element name to find, if any
value
  Attribute value, if any

#### Return Value

Node or NULL if none found

#### Discussion

You should call mxmlIndexReset() prior to using this function for the first time with a particular set of "element" and "value" strings. Passing NULL for both "element" and "value" is equivalent to calling mxmlIndexEnum().

### mxmlIndexNew

Create a new index.

mxml_index_t *mxmlIndexNew (
mxml_node_t *node,
const char *element,
const char *attr
);

#### Parameters

node
  XML node tree
element
  Element to index or NULL for all
attr
  Attribute to index or NULL for none

#### Return Value

New index

#### Discussion

The index will contain all nodes that contain the named element and/or attribute. If both "element" and "attr" are NULL, then the index will contain a sorted list of the elements in the node tree. Nodes are sorted by element name and optionally by attribute value if the "attr" argument is not NULL.

### mxmlIndexReset

Reset the enumeration/find pointer in the index and return the first node in the index.

mxml_node_t *mxmlIndexReset (
mxml_index_t *ind
);

#### Parameters

ind
  Index to reset

#### Return Value

First node or NULL if there is none

#### Discussion

This function should be called prior to using mxmlIndexEnum() or mxmlIndexFind() for the first time.

### mxmlLoadFd

Load a file descriptor into an XML node tree.

mxml_node_t *mxmlLoadFd (
mxml_node_t *top,
int fd,
mxml_load_cb_t cb
);

#### Parameters

top
  Top node
fd
  File descriptor to read from
cb
  Callback function or MXML_NO_CALLBACK

#### Return Value

First node or NULL if the file could not be read.

#### Discussion

The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

### mxmlLoadFile

Load a file into an XML node tree.

mxml_node_t *mxmlLoadFile (
mxml_node_t *top,
FILE *fp,
mxml_load_cb_t cb
);

#### Parameters

top
  Top node
fp
  File to read from
cb
  Callback function or MXML_NO_CALLBACK

#### Return Value

First node or NULL if the file could not be read.

#### Discussion

The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

### mxmlLoadString

Load a string into an XML node tree.

mxml_node_t *mxmlLoadString (
mxml_node_t *top,
const char *s,
mxml_load_cb_t cb
);

#### Parameters

top
  Top node
s
  String to load
cb
  Callback function or MXML_NO_CALLBACK

#### Return Value

First node or NULL if the string has errors.

#### Discussion

The nodes in the specified string are added to the specified top node. If no top node is provided, the XML string MUST be well-formed with a single parent node like <?xml> for the entire string. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

### Mini-XML 2.3 mxmlNewCDATA

Create a new CDATA node.

mxml_node_t *mxmlNewCDATA (
mxml_node_t *parent,
const char *data
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
data
  Data string

#### Return Value

New node

#### Discussion

The new CDATA node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new CDATA node has no parent. The data string must be nul-terminated and is copied into the new node. CDATA nodes use the MXML_ELEMENT type.

### Mini-XML 2.1 mxmlNewCustom

Create a new custom data node.

mxml_node_t *mxmlNewCustom (
mxml_node_t *parent,
void *data,
mxml_custom_destroy_cb_t destroy
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
data
  Pointer to data
destroy
  Function to destroy data

#### Return Value

New node

#### Discussion

The new custom node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new element node has no parent. NULL can be passed when the data in the node is not dynamically allocated or is separately managed.

### mxmlNewElement

Create a new element node.

mxml_node_t *mxmlNewElement (
mxml_node_t *parent,
const char *name
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
name
  Name of element

#### Return Value

New node

#### Discussion

The new element node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new element node has no parent.

### mxmlNewInteger

Create a new integer node.

mxml_node_t *mxmlNewInteger (
mxml_node_t *parent,
int integer
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
integer
  Integer value

#### Return Value

New node

#### Discussion

The new integer node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new integer node has no parent.

### mxmlNewOpaque

Create a new opaque string.

mxml_node_t *mxmlNewOpaque (
mxml_node_t *parent,
const char *opaque
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
opaque
  Opaque string

#### Return Value

New node

#### Discussion

The new opaque node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new opaque node has no parent. The opaque string must be nul-terminated and is copied into the new node.

### mxmlNewReal

Create a new real number node.

mxml_node_t *mxmlNewReal (
mxml_node_t *parent,
double real
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
real
  Real number value

#### Return Value

New node

#### Discussion

The new real number node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new real number node has no parent.

### mxmlNewText

Create a new text fragment node.

mxml_node_t *mxmlNewText (
mxml_node_t *parent,
int whitespace,
const char *string
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
whitespace
  1 = leading whitespace, 0 = no whitespace
string
  String

#### Return Value

New node

#### Discussion

The new text node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new text node has no parent. The whitespace parameter is used to specify whether leading whitespace is present before the node. The text string must be nul-terminated and is copied into the new node.

### mxmlNewTextf

Create a new formatted text fragment node.

mxml_node_t *mxmlNewTextf (
mxml_node_t *parent,
int whitespace,
const char *format,
...
);

#### Parameters

parent
  Parent node or MXML_NO_PARENT
whitespace
  1 = leading whitespace, 0 = no whitespace
format
  Printf-style frmat string
...
  Additional args as needed

#### Return Value

New node

#### Discussion

The new text node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new text node has no parent. The whitespace parameter is used to specify whether leading whitespace is present before the node. The format string must be nul-terminated and is formatted into the new node.

### Mini-XML 2.3 mxmlNewXML

Create a new XML document tree.

mxml_node_t *mxmlNewXML (
const char *version
);

#### Parameters

version
  Version number to use

#### Return Value

New ?xml node

#### Discussion

The "version" argument specifies the version number to put in the ?xml element node. If NULL, version 1.0 is assumed.

### Mini-XML 2.3 mxmlRelease

Release a node.

int mxmlRelease (
mxml_node_t *node
);

#### Parameters

node
  Node

#### Return Value

New reference count

#### Discussion

When the reference count reaches zero, the node (and any children) is deleted via mxmlDelete().

### mxmlRemove

Remove a node from its parent.

void mxmlRemove (
mxml_node_t *node
);

#### Parameters

node
  Node to remove

#### Discussion

Does not free memory used by the node - use mxmlDelete() for that. This function does nothing if the node has no parent.

### Mini-XML 2.3 mxmlRetain

Retain a node.

int mxmlRetain (
mxml_node_t *node
);

#### Parameters

node
  Node

#### Return Value

New reference count

### Mini-XML 2.3 mxmlSAXLoadFd

Load a file descriptor into an XML node tree using a SAX callback.

mxml_node_t *mxmlSAXLoadFd (
mxml_node_t *top,
int fd,
mxml_load_cb_t cb,
mxml_sax_cb_t sax_cb,
void *sax_data
);

#### Parameters

top
  Top node
fd
  File descriptor to read from
cb
  Callback function or MXML_NO_CALLBACK
sax_cb
  SAX callback or MXML_NO_CALLBACK
sax_data
  SAX user data

#### Return Value

First node or NULL if the file could not be read.

#### Discussion

The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.
The SAX callback must call mxmlRetain() for any nodes that need to be kept for later use. Otherwise, nodes are deleted when the parent node is closed or after each data, comment, CDATA, or directive node.

### Mini-XML 2.3 mxmlSAXLoadFile

Load a file into an XML node tree using a SAX callback.

mxml_node_t *mxmlSAXLoadFile (
mxml_node_t *top,
FILE *fp,
mxml_load_cb_t cb,
mxml_sax_cb_t sax_cb,
void *sax_data
);

#### Parameters

top
  Top node
fp
  File to read from
cb
  Callback function or MXML_NO_CALLBACK
sax_cb
  SAX callback or MXML_NO_CALLBACK
sax_data
  SAX user data

#### Return Value

First node or NULL if the file could not be read.

#### Discussion

The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.
The SAX callback must call mxmlRetain() for any nodes that need to be kept for later use. Otherwise, nodes are deleted when the parent node is closed or after each data, comment, CDATA, or directive node.

### Mini-XML 2.3 mxmlSAXLoadString

Load a string into an XML node tree using a SAX callback.

mxml_node_t *mxmlSAXLoadString (
mxml_node_t *top,
const char *s,
mxml_load_cb_t cb,
mxml_sax_cb_t sax_cb,
void *sax_data
);

#### Parameters

top
  Top node
s
  String to load
cb
  Callback function or MXML_NO_CALLBACK
sax_cb
  SAX callback or MXML_NO_CALLBACK
sax_data
  SAX user data

#### Return Value

First node or NULL if the string has errors.

#### Discussion

The nodes in the specified string are added to the specified top node. If no top node is provided, the XML string MUST be well-formed with a single parent node like <?xml> for the entire string. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes.
The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.
The SAX callback must call mxmlRetain() for any nodes that need to be kept for later use. Otherwise, nodes are deleted when the parent node is closed or after each data, comment, CDATA, or directive node.

### mxmlSaveAllocString

Save an XML node tree to an allocated string.

char *mxmlSaveAllocString (
mxml_node_t *node,
mxml_save_cb_t cb
);

#### Parameters

node
  Node to write
cb
  Whitespace callback or MXML_NO_CALLBACK

#### Return Value

Allocated string or NULL

#### Discussion

This function returns a pointer to a string containing the textual representation of the XML node tree. The string should be freed using the free() function when you are done with it. NULL is returned if the node would produce an empty string or if the string cannot be allocated.
The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

### mxmlSaveFd

Save an XML tree to a file descriptor.

int mxmlSaveFd (
mxml_node_t *node,
int fd,
mxml_save_cb_t cb
);

#### Parameters

node
  Node to write
fd
  File descriptor to write to
cb
  Whitespace callback or MXML_NO_CALLBACK

#### Return Value

0 on success, -1 on error.

#### Discussion

The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

### mxmlSaveFile

Save an XML tree to a file.

int mxmlSaveFile (
mxml_node_t *node,
FILE *fp,
mxml_save_cb_t cb
);

#### Parameters

node
  Node to write
fp
  File to write to
cb
  Whitespace callback or MXML_NO_CALLBACK

#### Return Value

0 on success, -1 on error.

#### Discussion

The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

### mxmlSaveString

Save an XML node tree to a string.

int mxmlSaveString (
mxml_node_t *node,
char *buffer,
int bufsize,
mxml_save_cb_t cb
);

#### Parameters

node
  Node to write
buffer
  String buffer
bufsize
  Size of string buffer
cb
  Whitespace callback or MXML_NO_CALLBACK

#### Return Value

Size of string

#### Discussion

This function returns the total number of bytes that would be required for the string but only copies (bufsize - 1) characters into the specified buffer.
The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

### Mini-XML 2.3 mxmlSetCDATA

Set the element name of a CDATA node.

int mxmlSetCDATA (
mxml_node_t *node,
const char *data
);

#### Parameters

node
  Node to set
data
  New data string

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not a CDATA element node.

### Mini-XML 2.1 mxmlSetCustom

Set the data and destructor of a custom data node.

int mxmlSetCustom (
mxml_node_t *node,
void *data,
mxml_custom_destroy_cb_t destroy
);

#### Parameters

node
  Node to set
data
  New data pointer
destroy
  New destructor function

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not a custom node.

### mxmlSetCustomHandlers

Set the handling functions for custom data.

void mxmlSetCustomHandlers (
mxml_custom_load_cb_t load,
mxml_custom_save_cb_t save
);

#### Parameters

load
  Load function
save
  Save function

#### Discussion

The load function accepts a node pointer and a data string and must return 0 on success and non-zero on error.
The save function accepts a node pointer and must return a malloc'd string on success and NULL on error.

### mxmlSetElement

Set the name of an element node.

int mxmlSetElement (
mxml_node_t *node,
const char *name
);

#### Parameters

node
  Node to set
name
  New name string

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not an element node.

### mxmlSetErrorCallback

Set the error message callback.

void mxmlSetErrorCallback (
mxml_error_cb_t cb
);

#### Parameters

cb
  Error callback function

### mxmlSetInteger

Set the value of an integer node.

int mxmlSetInteger (
mxml_node_t *node,
int integer
);

#### Parameters

node
  Node to set
integer
  Integer value

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not an integer node.

### mxmlSetOpaque

Set the value of an opaque node.

int mxmlSetOpaque (
mxml_node_t *node,
const char *opaque
);

#### Parameters

node
  Node to set
opaque
  Opaque string

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not an opaque node.

### mxmlSetReal

Set the value of a real number node.

int mxmlSetReal (
mxml_node_t *node,
double real
);

#### Parameters

node
  Node to set
real
  Real number value

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not a real number node.

### mxmlSetText

Set the value of a text node.

int mxmlSetText (
mxml_node_t *node,
int whitespace,
const char *string
);

#### Parameters

node
  Node to set
whitespace
  1 = leading whitespace, 0 = no whitespace
string
  String

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not a text node.

### mxmlSetTextf

Set the value of a text node to a formatted string.

int mxmlSetTextf (
mxml_node_t *node,
int whitespace,
const char *format,
...
);

#### Parameters

node
  Node to set
whitespace
  1 = leading whitespace, 0 = no whitespace
format
  Printf-style format string
...
  Additional arguments as needed

#### Return Value

0 on success, -1 on failure

#### Discussion

The node is not changed if it is not a text node.

### Mini-XML 2.3 mxmlSetWrapMargin

Set the the wrap margin when saving XML data.

void mxmlSetWrapMargin (
int column
);

#### Parameters

column
  Column for wrapping

#### Discussion

Wrapping is disabled when "column" is <= 0.

### mxmlWalkNext

Walk to the next logical node in the tree.

mxml_node_t *mxmlWalkNext (
mxml_node_t *node,
mxml_node_t *top,
int descend
);

#### Parameters

node
  Current node
top
  Top node
descend
  Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Return Value

Next node or NULL

#### Discussion

The descend argument controls whether the first child is considered to be the next node. The top node argument constrains the walk to the node's children.

### mxmlWalkPrev

Walk to the previous logical node in the tree.

mxml_node_t *mxmlWalkPrev (
mxml_node_t *node,
mxml_node_t *top,
int descend
);

#### Parameters

node
  Current node
top
  Top node
descend
  Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Return Value

Previous node or NULL

#### Discussion

The descend argument controls whether the previous node's last child is considered to be the previous node. The top node argument constrains the walk to the node's children.

## Data Types

### mxml_attr_t

An XML element attribute value.

typedef struct mxml_attr_s mxml_attr_t;

### mxml_custom_destroy_cb_t

Custom data destructor

typedef void (*mxml_custom_destroy_cb_t)(void *);

### mxml_custom_load_cb_t

Custom data load callback function

typedef int (*mxml_custom_load_cb_t)( mxml_node_t *, const char *);

### mxml_custom_save_cb_t

Custom data save callback function

typedef char *(*mxml_custom_save_cb_t)( mxml_node_t *);

### Mini-XML 2.1 mxml_custom_t

An XML custom value.

typedef struct mxml_custom_s mxml_custom_t;

### mxml_element_t

An XML element value.

typedef struct mxml_element_s mxml_element_t;

### mxml_error_cb_t

Error callback function

typedef void (*mxml_error_cb_t)(const char *);

### mxml_index_t

An XML node index.

typedef struct mxml_index_s mxml_index_t;

### mxml_load_cb_t

Load callback function

typedef mxml_type_t (*mxml_load_cb_t)( mxml_node_t *);

### mxml_node_t

An XML node.

typedef struct mxml_node_s mxml_node_t;

### mxml_save_cb_t

Save callback function

typedef const char *(*mxml_save_cb_t)( mxml_node_t *, int);

### mxml_sax_cb_t

SAX callback function

typedef void (*mxml_sax_cb_t)( mxml_node_t *, mxml_sax_event_t, void *);

### mxml_sax_event_t

SAX event type.

typedef enum mxml_sax_event_e mxml_sax_event_t;

### mxml_text_t

An XML text value.

typedef struct mxml_text_s mxml_text_t;

### mxml_value_t

An XML node value.

typedef union mxml_value_u mxml_value_t;

## Structures

### mxml_attr_s

An XML element attribute value.

struct mxml_attr_s {
char *name;
char *value;
};

#### Members

name
  Attribute name
value
  Attribute value

### Mini-XML 2.1 mxml_custom_s

An XML custom value.

struct mxml_custom_s {
void *data;
mxml_custom_destroy_cb_t destroy;
};

#### Members

data
  Pointer to (allocated) custom data
destroy
  Pointer to destructor function

### mxml_element_s

An XML element value.

struct mxml_element_s {
mxml_attr_t *attrs;
char *name;
int num_attrs;
};

#### Members

attrs
  Attributes
name
  Name of element
num_attrs
  Number of attributes

### mxml_index_s

An XML node index.

struct mxml_index_s {
int alloc_nodes;
char *attr;
int cur_node;
mxml_node_t **nodes;
int num_nodes;
};

#### Members

alloc_nodes
  Allocated nodes in index
attr
  Attribute used for indexing or NULL
cur_node
  Current node
nodes
  Node array
num_nodes
  Number of nodes in index

### mxml_node_s

An XML node.

struct mxml_node_s {
struct mxml_node_s *child;
struct mxml_node_s *last_child;
struct mxml_node_s *next;
struct mxml_node_s *parent;
struct mxml_node_s *prev;
int ref_count;
mxml_type_t type;
void *user_data;
mxml_value_t value;
};

#### Members

child
  First child node
last_child
  Last child node
next
  Next node under same parent
parent
  Parent node
prev
  Previous node under same parent
ref_count
  Use count
type
  Node type
user_data
  User data
value
  Node value

### mxml_text_s

An XML text value.

struct mxml_text_s {
char *string;
int whitespace;
};

#### Members

string
  Fragment string
whitespace
  Leading whitespace?

## Unions

### mxml_value_u

An XML node value.

union mxml_value_u {
mxml_custom_t custom;
mxml_element_t element;
int integer;
char *opaque;
double real;
mxml_text_t text;
};

#### Members

custom Mini-XML 2.1
  Custom data
element
  Element
integer
  Integer number
opaque
  Opaque string
real
  Real number
text
  Text fragment

## Constants

### mxml_sax_event_e

SAX event type.

#### Constants

MXML_SAX_CDATA
  CDATA node
MXML_SAX_COMMENT
  Comment node
MXML_SAX_DATA
  Data node
MXML_SAX_DIRECTIVE
  Processing directive node
MXML_SAX_ELEMENT_CLOSE
  Element closed
MXML_SAX_ELEMENT_OPEN
  Element opened

### mxml_type_e

The XML node type.

#### Constants

MXML_CUSTOM Mini-XML 2.1
  Custom data
MXML_ELEMENT
  XML element with attributes
MXML_IGNORE Mini-XML 2.3
  Ignore/throw away node
MXML_INTEGER
  Integer value
MXML_OPAQUE
  Opaque string
MXML_REAL
  Real value
MXML_TEXT
  Text fragment

# XML Schema

This appendix provides the XML schema that is used for the XML files produced by `mxmldoc`. This schema is available on-line at:

        http://www.easysw.com/~mike/mxmldoc.xsd

## mxmldoc.xsd

    <?xml version="1.0"?>
    <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
      <xsd:annotation>
        <xsd:documentation xml:lang="en">
          Mini-XML 2.3 documentation schema for mxmldoc output.
          Copyright 2003-2007 by Michael Sweet.
        </xsd:documentation>
      </xsd:annotation>

      <!-- basic element definitions -->
      <xsd:element name="argument" type="argumentType"/>
      <xsd:element name="class" type="classType"/>
      <xsd:element name="constant" type="constantType"/>
      <xsd:element name="description" type="xsd:string"/>
      <xsd:element name="enumeration" type="enumerationType"/>
      <xsd:element name="function" type="functionType"/>
      <xsd:element name="mxmldoc" type="mxmldocType"/>
      <xsd:element name="namespace" type="namespaceType"/>
      <xsd:element name="returnvalue" type="returnvalueType"/>
      <xsd:element name="seealso" type="identifierList"/>
      <xsd:element name="struct" type="structType"/>
      <xsd:element name="typedef" type="typedefType"/>
      <xsd:element name="type" type="xsd:string"/>
      <xsd:element name="union" type="unionType"/>
      <xsd:element name="variable" type="variableType"/>

      <!-- descriptions of complex elements -->
      <xsd:complexType name="argumentType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="default" type="xsd:string" use="optional"/>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="direction" type="direction" use="optional"
         default="I"/>
      </xsd:complexType>

      <xsd:complexType name="classType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="class"/>
    	<xsd:element ref="enumeration"/>
    	<xsd:element ref="function"/>
    	<xsd:element ref="struct"/>
    	<xsd:element ref="typedef"/>
    	<xsd:element ref="union"/>
    	<xsd:element ref="variable"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="parent" type="xsd:string" use="optional"/>
      </xsd:complexType>

      <xsd:complexType name="constantType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="enumerationType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="constant" minOccurs="1" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="functionType">
        <xsd:sequence>
          <xsd:element ref="returnvalue" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="argument" minOccurs="1" maxOccurs="unbounded"/>
          <xsd:element ref="seealso" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="scope" type="scope" use="optional"/>
      </xsd:complexType>

      <xsd:complexType name="mxmldocType">
        <xsd:choice minOccurs="0" maxOccurs="unbounded">
          <xsd:element ref="class"/>
          <xsd:element ref="enumeration"/>
          <xsd:element ref="function"/>
          <xsd:element ref="namespace"/>
          <xsd:element ref="struct"/>
          <xsd:element ref="typedef"/>
          <xsd:element ref="union"/>
          <xsd:element ref="variable"/>
        </xsd:choice>
      </xsd:complexType>

      <xsd:complexType name="namespaceType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="class"/>
    	<xsd:element ref="enumeration"/>
    	<xsd:element ref="function"/>
    	<xsd:element ref="struct"/>
    	<xsd:element ref="typedef"/>
    	<xsd:element ref="union"/>
    	<xsd:element ref="variable"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="returnvalueType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
      </xsd:complexType>

      <xsd:complexType name="structType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="variable"/>
    	<xsd:element ref="function"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="typedefType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="unionType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="variable" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="variableType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <!-- data types -->
      <xsd:simpleType name="direction">
        <xsd:restriction base="xsd:string">
          <xsd:enumeration value="I"/>
          <xsd:enumeration value="O"/>
          <xsd:enumeration value="IO"/>
        </xsd:restriction>
      </xsd:simpleType>

      <xsd:simpleType name="identifier">
        <xsd:restriction base="xsd:string">
          <xsd:pattern value="[a-zA-Z_(.]([a-zA-Z_(.,)* 0-9])*"/>
        </xsd:restriction>
      </xsd:simpleType>

      <xsd:simpleType name="identifierList">
        <xsd:list itemType="identifier"/>
      </xsd:simpleType>

      <xsd:simpleType name="scope">
        <xsd:restriction base="xsd:string">
          <xsd:enumeration value=""/>
          <xsd:enumeration value="private"/>
          <xsd:enumeration value="protected"/>
          <xsd:enumeration value="public"/>
        </xsd:restriction>
      </xsd:simpleType>
    </xsd:schema>