MAKE(1)                    OpenBSD Reference Manual                    MAKE(1)

NAME
     make - maintain program dependencies

SYNOPSIS
     make [-BeiknPqrSst] [-D variable] [-d flags] [-f makefile] [-I directory]
          [-j max_jobs] [-m directory] [-V variable] [NAME=value] [target ...]

DESCRIPTION
     make is a program designed to simplify the maintenance of other programs.
     Its input is a list of specifications as to the files upon which programs
     and other files depend.  If the file `BSDmakefile' exists, it is read for
     this list of specifications.  If it does not exist, the files `makefile'
     and `Makefile' are tried in order.  If the file `.depend' exists, it is
     read in addition to the makefile (see mkdep(1)).

     The handling of `BSDmakefile' and `.depend' are BSD extensions.

     Standard options are as follows:

     -e      Specify that environment variables override macro assignments
             within makefiles.

     -f makefile
             Specify a makefile to read instead of the default `makefile' and
             `Makefile'.  If makefile is `-', standard input is read.  Multi-
             ple makefiles may be specified, and are read in the order speci-
             fied.

     -i      Ignore non-zero exit of shell commands in the makefile.  Equiva-
             lent to specifying `-' before each command line in the makefile.

     -k      Continue processing after errors are encountered, but only on
             those targets that do not depend on the target whose creation
             caused the error.

     -n      Display the commands that would have been executed, but do not
             actually execute them.

     -q      Do not execute any commands, but exit with status 0 if the speci-
             fied targets are up-to-date, and 1 otherwise.

     -r      Do not use the built-in rules specified in the system makefile.

     -S      Stop processing when an error is encountered.  This is the de-
             fault behavior.  This is needed to negate the -k option during
             recursive builds.

     -s      Do not echo commands as they are executed.  Equivalent to speci-
             fying `@' before each command line in the makefile.

     -t      Rather than re-building a target as specified in the makefile,
             create it or update its modification time to make it appear up-
             to-date.

     NAME=value
             Set the value of the variable NAME to value.

     Extended options are as follows:

     -B      Try to be backwards compatible by executing a single shell per
             command and by executing the commands to make the sources of a
             dependency line in sequence.  This is turned on by default unless
             -j is used.

     -D variable
             Define variable to be 1.

     -d flags
             Turn on debugging, and specify which portions of make are to
             print debugging information.  flags is one or more of the follow-
             ing:

             A       Print all possible debugging information; equivalent to
                     specifying all of the debugging flags.

             a       Print debugging information about archive searching and
                     caching.

             c       Print debugging information about conditional evaluation.

             d       Print debugging information about directory searching and
                     caching.

             f       Print debugging information about the expansion of for
                     loops.

             g1      Print the input graph before making anything.

             g2      Print the input graph after making everything, or before
                     exiting on error.

             J       Print job tokens showing which output corresponds to what
                     job.

             j       Print debugging information about running multiple
                     shells.

             l       Print commands in Makefile targets regardless of whether
                     or not they are prefixed by @.  Also known as loud behav-
                     ior.

             m       Print debugging information about making targets, includ-
                     ing modification dates.

             n       Print debugging information about target names equiva-
                     lence computations.

             p       Help finding concurrency issues for parallel make by
                     adding some randomization.  If RANDOM_ORDER is defined,
                     targets will be shuffled before being built.  If
                     RANDOM_DELAY is defined, make will wait between 0 and
                     ${RANDOM_DELAY} seconds at the start of each job.  A giv-
                     en random seed can be forced by setting RANDOM_SEED, but
                     this does not guarantee reproductibility.

             s       Print debugging information about suffix-transformation
                     rules.

             t       Print debugging information about target list mainte-
                     nance.

             v       Print debugging information about variable assignment.

     -I directory
             Specify a directory in which to search for makefiles and included
             makefiles.  The system makefile directory (or directories, see
             the -m option) is automatically included as part of this list.

     -j max_jobs
             Specify the maximum number of jobs that make may have running at
             any one time.  Turns compatibility mode off, unless the -B flag
             is also specified.

     -m directory
             Specify a directory in which to search for sys.mk and makefiles
             included via the <...> style.  Multiple directories can be added
             to form a search path.  This path will override the default sys-
             tem include path: /usr/share/mk.  Furthermore, the system include
             path will be appended to the search path used for "..."-style in-
             clusions (see the -I option).

     -P      Collate the output of a given job and display it only when the
             job finishes, instead of mixing the output of parallel jobs to-
             gether.  This option has no effect unless -j is used too.

     -V variable
             Print make's idea of the value of variable.  Do not build any
             targets.  Multiple instances of this option may be specified; the
             variables will be printed one per line, with a blank line for
             each null or undefined variable.

     There are seven different types of lines in a makefile: file dependency
     specifications, shell commands, variable assignments, include statements,
     conditional directives, for loops, and comments.  Of these, include
     statements, conditional directives and for loops are extensions.

     In general, lines may be continued from one line to the next by ending
     them with a backslash (`\').  The trailing newline character and initial
     whitespace on the following line are compressed into a single space.

FILE DEPENDENCY SPECIFICATIONS
     Dependency lines consist of one or more targets, an operator, and zero or
     more sources.  This creates a relationship where the targets ``depend''
     on the sources and are usually created from them.  The exact relationship
     between the target and the source is determined by the operator that sep-
     arates them.  Note that the use of several targets is merely a shorthand
     for duplicate rules.  Specifically,

           target1 target2: depa depb
                   cmd1
                   cmd2

     is just a short form of

           target1: depa depb
                   cmd1
                   cmd2
           target2: depa depb
                   cmd1
                   cmd2

     make does not support Solaris syntax for true multiple targets:

           target1 + target2: depa depb
                   cmd1
                   cmd2

     The operators are as follows:

     :     A target is considered out-of-date if its modification time is less
           than those of any of its sources.  Sources for a target accumulate
           over dependency lines when this operator is used.  The target is
           removed if make is interrupted.

     !     Targets are always re-created, but not until all sources have been
           examined and re-created as necessary.  Sources for a target accumu-
           late over dependency lines when this operator is used.  The target
           is removed if make is interrupted.

     ::    If no sources are specified, the target is always re-created.  Oth-
           erwise, a target is considered out-of-date if any of its sources
           has been modified more recently than the target.  Sources for a
           target do not accumulate over dependency lines when this operator
           is used.  The target will not be removed if make is interrupted.

     The :: operator is a fairly standard extension.  The ! operator is a BSD
     extension.

     As an extension, targets and sources may contain the shell wildcard ex-
     pressions `?', `*', `[]' and `{}'.  The expressions `?', `*' and `[]' may
     only be used as part of the final component of the target or source, and
     must be used to describe existing files.  The expression `{}' need not
     necessarily be used to describe existing files.  Expansion is in directo-
     ry order, not alphabetically as done in the shell.

     For maximum portability, target names should only consist of periods, un-
     derscores, digits and alphabetic characters.

SHELL COMMANDS
     Each target may have associated with it a series of shell commands, nor-
     mally used to create the target.  Each of the commands in this script
     must be preceded by a tab.  While any target may appear on a dependency
     line, only one of these dependencies may be followed by a creation
     script, unless the `::' operator is used.

     If a command line begins with a combination of the characters, `@', `-'
     and/or `+', the command is treated specially:

     `@'  causes the command not to be echoed before it is executed.

     `-'  causes any non-zero exit status of the command line to be ignored.

     `+'  causes the command to be executed even if -n has been specified.
          (This can be useful to debug recursive Makefiles.)

     The command is always executed using /bin/sh in "set -e" mode.

VARIABLE ASSIGNMENTS
     Variables in make are much like variables in the shell, and, by tradi-
     tion, consist of all upper-case letters.  They are also called `macros'
     in various texts.  For portability, only periods, underscores, digits and
     letters should be used for variable names.  The five operators that can
     be used to assign values to variables are as follows:

     =       Assign the value to the variable.  Any previous value is overrid-
             den.

     :=      Assign with expansion, i.e., expand the value before assigning it
             to the variable (extension).

     +=      Append the value to the current value of the variable (exten-
             sion).

     ?=      Assign the value to the variable if it is not already defined
             (BSD extension).  Normally, expansion is not done until the vari-
             able is referenced.

     !=      Expand the value and pass it to the shell for execution and as-
             sign the result to the variable.  Any newlines in the result are
             replaced with spaces (BSD extension).

     Any whitespace before the assigned value is removed; if the value is be-
     ing appended, a single space is inserted between the previous contents of
     the variable and the appended value.

     Variables are expanded by surrounding the variable name with either curly
     braces (`{}') or parentheses (`()') and preceding it with a dollar sign
     (`$').  If the variable name contains only a single letter, the surround-
     ing braces or parentheses are not required.  This shorter form is not
     recommended.

     Variable substitution occurs at two distinct times, depending on where
     the variable is being used.  Variables in dependency lines are expanded
     as the line is read.  Variables in shell commands are expanded when the
     shell command is executed.

     The four different classes of variables (in order of increasing prece-
     dence) are:

     Environment variables
             Variables defined as part of make's environment.

     Global variables
             Variables defined in the makefile or in included makefiles.

     Command line variables
             Variables defined as part of the command line.

     Local variables
             Variables that are defined specific to a certain target.  Stan-
             dard local variables are as follows:

             @         The name of the target.

             %         The name of the archive member (only valid for library
                       rules).

             !         The name of the archive file (only valid for library
                       rules).

             ?         The list of prerequisites for this target that were
                       deemed out-of-date.

             <         The name of the source from which this target is to be
                       built, if a valid implied rule (suffix rule) is in
                       scope.

             *         The file prefix of the file, containing only the file
                       portion, no suffix or preceding directory components.

             The six variables `@F', `@D', `<F', `<D', `*F', and `*D' yield
             the "filename" and "directory" parts of the corresponding macros.

             For maximum compatibility, `<' should only be used for actual im-
             plied rules.  It is also set when there is an implied rule that
             matches the current dependency in scope.  That is, in

                   .SUFFIXES: .c .o
                   file.o: file.c
                           cmd1 $<

                   .c.o:
                           cmd2

             building file.o will execute "cmd1 file.c".

             As an extension, make supports the following local variables:

             >         The list of all sources for this target.

             .ALLSRC   Synonym for `>'.

             .ARCHIVE  Synonym for `!'.

             .IMPSRC   Synonym for `<'.

             .MEMBER   Synonym for `%'.

             .OODATE   Synonym for `?'.

             .PREFIX   Synonym for `*'.

             .TARGET   Synonym for `@'.

             These variables may be used on the dependency half of dependency
             lines, when they make sense.

     In addition, make sets or knows about the following internal variables,
     or environment variables:

     $          A single dollar sign `$', i.e., `$$' expands to a single dol-
                lar sign.

     .MAKE      The name that make was executed with (argv[0]).

     .CURDIR    A path to the directory where make was executed.

     .OBJDIR    A path to the directory where the targets are built.  At
                startup, make searches for an alternate directory to place
                target files -- it will attempt to change into this special
                directory.  First, if MAKEOBJDIRPREFIX is defined, make
                prepends its contents to the current directory name and tries
                for the resulting directory.  If that fails, make remains in
                the current directory.  If MAKEOBJDIRPREFIX is not defined,
                make checks MAKEOBJDIR and tries to change into that directo-
                ry.  Should that fail, make remains in the current directory.
                If MAKEOBJDIR is not defined, it tries to change into the di-
                rectory named obj.${MACHINE} (see MACHINE variable).  If it
                still has found no special directory, make next tries the di-
                rectory named obj.  If this fails, make tries to prepend
                /usr/obj to the current directory name.  Finally, if none of
                these directories are available make will settle for and use
                the current directory.

     .MAKEFLAGS
                The environment variable MAKEFLAGS may contain anything that
                may be specified on make's command line.  Its contents are
                stored in make's .MAKEFLAGS variable.  Anything specified on
                make's command line is appended to the .MAKEFLAGS variable
                which is then entered into the environment as MAKEFLAGS for
                all programs which make executes.

     MFLAGS     A shorter synonym for .MAKEFLAGS.

     PWD        Alternate path to the current directory.  make normally sets
                `.CURDIR' to the canonical path given by getcwd(3).  However,
                if the environment variable PWD is set and gives a path to the
                current directory, then make sets `.CURDIR' to the value of
                PWD instead.  PWD is always set to the value of `.OBJDIR' for
                all programs which make executes.

     .TARGETS   List of targets make is currently building.

     .INCLUDES  See .INCLUDES special target.

     .LIBS      See .LIBS special target.

     MACHINE    Name of the machine architecture make is running on, obtained
                from the MACHINE environment variable, or through uname(3) if
                not defined.

     MACHINE_ARCH
                Name of the machine architecture make was compiled for, ob-
                tained from the MACHINE_ARCH environment variable, or defined
                at compilation time.

     MACHINE_CPU
                Name of the machine processor make was compiled for, obtained
                from the MACHINE_CPU environment variable, or defined at com-
                pilation time.  On processors where only one endianness is
                possible, the value of this variable is always the same as
                MACHINE_ARCH.

     MAKEFILE   Possibly the file name of the last makefile that has been
                read.  It should not be used; see the BUGS section below.

     Variable expansion may be modified to select or modify each word of the
     variable (where ``word'' is a whitespace delimited sequence of charac-
     ters).  The general format of a variable expansion is as follows:

           {variable[:modifier[:...]]}

     Each modifier begins with a colon and one of the following special char-
     acters.  The colon may be escaped with a backslash (`\').

     :E      Replaces each word in the variable with its suffix.

     :H      Replaces each word in the variable with everything but the last
             component.

     :L      Replaces each word in the variable with its lower case equiva-
             lent.

     :U      Replaces each word in the variable with its upper case equiva-
             lent.

     :Mpattern
             Select only those words that match the rest of the modifier.  The
             standard shell wildcard characters (`*', `?', and `[]') may be
             used.  The wildcard characters may be escaped with a backslash
             (`\').

     :Npattern
             This is identical to :M, but selects all words which do not match
             the rest of the modifier.

     :Q      Quotes every shell meta-character in the variable, so that it can
             be passed safely through recursive invocations of make.

     :R      Replaces each word in the variable with everything but its suf-
             fix.

     :S/old_string/new_string/[1g]
             Modify the first occurrence of old_string in the variable's val-
             ue, replacing it with new_string.  If a `g' is appended to the
             last slash of the pattern, all occurrences in each word are re-
             placed.  If a `1' is appended to the last slash of the pattern,
             only the first word is affected.  If old_string begins with a
             caret (`^'), old_string is anchored at the beginning of each
             word.  If old_string ends with a dollar sign (`$'), it is an-
             chored at the end of each word.  Inside new_string, an ampersand
             (`&') is replaced by old_string (without any `^' or `$').  Any
             character may be used as a delimiter for the parts of the modifi-
             er string.  The anchoring, ampersand and delimiter characters may
             be escaped with a backslash (`\').

             Variable expansion occurs in the normal fashion inside both
             old_string and new_string with the single exception that a back-
             slash is used to prevent the expansion of a dollar sign (`$'),
             not a preceding dollar sign as is usual.

     :C/pattern/replacement/[1g]
             The :C modifier is just like the :S modifier except that the old
             and new strings, instead of being simple strings, are a regular
             expression (see regex(3)) and an ed(1)-style replacement string.
             Normally, the first occurrence of the pattern in each word of the
             value is changed.  The `1' modifier causes the substitution to
             apply to at most one word; the `g' modifier causes the substitu-
             tion to apply to as many instances of the search pattern as occur
             in the word or words it is found in.  Note that `1' and `g' are
             orthogonal; the former specifies whether multiple words are po-
             tentially affected, the latter whether multiple substitutions can
             potentially occur within each affected word.

     :T      Replaces each word in the variable with its last component.

     :old_string=new_string
             This is the AT&T System V UNIX style variable substitution.  It
             must be the last modifier specified.  If old_string or new_string
             do not contain the pattern matching character % then it is as-
             sumed that they are anchored at the end of each word, so only
             suffixes or entire words may be replaced.  Otherwise % is the
             substring of old_string to be replaced in new_string.

     All modifiers are BSD extensions, except for the standard AT&T System V
     UNIX style variable substitution.

INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
     Makefile inclusion, conditional structures and for loops reminiscent of
     the C programming language are provided in make.  All such structures are
     identified by a line beginning with a single dot (`.') character.
     Whitespace characters may follow this dot, e.g.,

           .include <file>
     and
           .   include <file>

     are identical constructs.  Files are included with either `.include
     <file>' or `.include "file"'.  Variables between the angle brackets or
     double quotes are expanded to form the file name.  If angle brackets are
     used, the included makefile is expected to be in the system makefile di-
     rectory.  If double quotes are used, the including makefile's directory
     and any directories specified using the -I option are searched before the
     system makefile directory.

     Conditional expressions are also preceded by a single dot as the first
     character of a line.  The possible conditionals are as follows:

     .undef variable
             Un-define the specified global variable.  Only global variables
             may be un-defined.

     .poison variable
             Poison the specified global variable.  Any further reference to
             variable will be flagged as an error.

     .poison !defined (variable)
             It is an error to try to use the value of variable in a context
             where it is not defined.

     .poison empty (variable)
             It is an error to try to use the value of variable in a context
             where it is not defined or empty.

     .if [!]expression [operator expression ...]
             Test the value of an expression.

     .ifdef [!]variable [operator variable ...]
             Test the value of a variable.

     .ifndef [!]variable [operator variable ...]
             Test the value of a variable.

     .ifmake [!]target [operator target ...]
             Test the target being built.

     .ifnmake [!]target [operator target ...]
             Test the target being built.

     .else   Reverse the sense of the last conditional.

     .elif [!]expression [operator expression ...]
             A combination of `.else' followed by `.if'.

     .elifdef [!]variable [operator variable ...]
             A combination of `.else' followed by `.ifdef'.

     .elifndef [!]variable [operator variable ...]
             A combination of `.else' followed by `.ifndef'.

     .elifmake [!]target [operator target ...]
             A combination of `.else' followed by `.ifmake'.

     .elifnmake [!]target [operator target ...]
             A combination of `.else' followed by `.ifnmake'.

     .endif  End the body of the conditional.

     The operator may be any one of the following:

     ||     logical OR

     &&     Logical AND; of higher precedence than ``||''.

     As in C, make will only evaluate a conditional as far as is necessary to
     determine its value.  Parentheses may be used to change the order of
     evaluation.  The boolean operator `!' may be used to logically negate an
     entire conditional.  It is of higher precedence than `&&'.

     The value of expression may be any of the following:

     defined  Takes a variable name as an argument and evaluates to true if
              the variable has been defined.

     make     Takes a target name as an argument and evaluates to true if the
              target was specified as part of make's command line or was de-
              clared the default target (either implicitly or explicitly, see
              .MAIN) before the line containing the conditional.

     empty    Takes a variable, with possible modifiers, and evaluates to true
              if the expansion of the variable would result in an empty
              string.

     exists   Takes a file name as an argument and evaluates to true if the
              file exists.  The file is searched for on the system search path
              (see .PATH).

     target   Takes a target name as an argument and evaluates to true if the
              target has been defined.

     expression may also be an arithmetic or string comparison.  Variable ex-
     pansion is performed on both sides of the comparison, after which the in-
     tegral values are compared.  A value is interpreted as hexadecimal if it
     is preceded by 0x, otherwise it is decimal; octal numbers are not sup-
     ported.  The standard C relational operators are all supported.  If after
     variable expansion, either the left or right hand side of a `==' or `!='
     operator is not an integral value, then string comparison is performed
     between the expanded variables.  If no relational operator is given, it
     is assumed that the expanded variable is being compared against 0.

     When make is evaluating one of these conditional expressions, and it en-
     counters a word it doesn't recognize, either the ``make'' or ``defined''
     expression is applied to it, depending on the form of the conditional.
     If the form is `.ifdef' or `.ifndef', the ``defined'' expression is ap-
     plied.  Similarly, if the form is `.ifmake' or `.ifnmake', the ``make''
     expression is applied.

     If the conditional evaluates to true the parsing of the makefile contin-
     ues as before.  If it evaluates to false, the following lines are
     skipped.  In both cases this continues until a `.else' or `.endif' is
     found.

     For loops are typically used to apply a set of rules to a list of files.
     The syntax of a for loop is:

           .for variable [variable ...] in expression
                   <make-rules>
           .endfor

     After the for expression is evaluated, it is split into words.  On each
     iteration of the loop, one word is assigned to each variable, in order,
     and these variables are substituted in the make-rules inside the body of
     the for loop.  The number of words must match the number of iteration
     variables; that is, if there are three iteration variables, the number of
     words must be a multiple of three.

     Loops and conditional expressions may nest arbitrarily, but they may not
     cross include file boundaries.

COMMENTS
     Comments begin with a hash (`#') character, anywhere but in a shell com-
     mand line, and continue to the end of the line.

SPECIAL SOURCES
     .IGNORE    Ignore any errors from the commands associated with this tar-
                get, exactly as if they all were preceded by a dash (`-').

     .MADE      Mark all sources of this target as being up-to-date.

     .MAKE      Execute the commands associated with this target even if the
                -n or -t options were specified.  Normally used to mark recur-
                sive make's.

     .NOTMAIN   Normally make selects the first target it encounters as the
                default target to be built if no target was specified.  This
                source prevents this target from being selected.

     .OPTIONAL  If a target is marked with this attribute and make can't fig-
                ure out how to create it, it will ignore this fact and assume
                the file isn't needed or already exists.

     .PRECIOUS  When make is interrupted, it removes any partially made tar-
                gets.  This source prevents the target from being removed.

     .SILENT    Do not echo any of the commands associated with this target,
                exactly as if they all were preceded by an at sign (`@').

     .USE       Turn the target into make's version of a macro.  When the tar-
                get is used as a source for another target, the other target
                acquires the commands, sources, and attributes (except for
                .USE) of the source.  If the target already has commands, the
                .USE target's commands are appended to them.

     .WAIT      If .WAIT appears in a dependency line, the sources that pre-
                cede it are made before the sources that succeed it in the
                line.  Loops are not detected and targets that form loops will
                be silently ignored.

SPECIAL TARGETS
     Special targets may not be included with other targets, i.e., they must
     be the only target specified.

     .BEGIN        Any command lines attached to this target are executed be-
                   fore anything else is done.

     .DEFAULT      This is sort of a .USE rule for any target (that was used
                   only as a source) that make can't figure out any other way
                   to create.  Only the shell script is used.  The .IMPSRC
                   variable of a target that inherits .DEFAULT's commands is
                   set to the target's own name.

     .END          Any command lines attached to this target are executed af-
                   ter everything else is done.

     .IGNORE       Mark each of the sources with the .IGNORE attribute.  If no
                   sources are specified, this is the equivalent of specifying
                   the -i option.

     .INCLUDES     A list of suffixes that indicate files that can be included
                   in a source file.  The suffix must have already been de-
                   clared with .SUFFIXES, any suffix so declared will have the
                   directories in its search path (see .PATH) placed in the
                   .INCLUDES special variable, each preceded by a -I flag.

     .INTERRUPT    If make is interrupted, the commands for this target will
                   be executed.

     .LIBS         This does for libraries what .INCLUDES does for include
                   files, except that the flag used is -L.

     .MAIN         If no target is specified when make is invoked, this target
                   will be built.  This is always set, either explicitly, or
                   implicitly when make selects the default target, to give
                   the user a way to refer to the default target on the com-
                   mand line.

     .MAKEFLAGS    This target provides a way to specify flags for make when
                   the makefile is used.  The flags are as if typed to the
                   shell, though the -f option will have no effect.

     .NOTPARALLEL  Disable parallel mode.

     .NO_PARALLEL  Same as above, for compatibility with other pmake variants.

     .ORDER        The named targets are made in sequence.

     .PATH         The sources are directories which are to be searched for
                   files not found in the current directory.  If no sources
                   are specified, any previously specified directories are
                   deleted.

     .PATHsuffix   The sources are directories which are to be searched for
                   suffixed files not found in the current directory.  make
                   first searches the suffixed search path, before reverting
                   to the default path if the file is not found there.

     .PHONY        Apply the .PHONY attribute to any specified sources.  Tar-
                   gets with this attribute are always considered to be out of
                   date.

     .PRECIOUS     Apply the .PRECIOUS attribute to any specified sources.  If
                   no sources are specified, the .PRECIOUS attribute is ap-
                   plied to every target in the file.

     .SILENT       Apply the .SILENT attribute to any specified sources.  If
                   no sources are specified, the .SILENT attribute is applied
                   to every command in the file.

     .SUFFIXES     Each source specifies a suffix to make.  If no sources are
                   specified, any previously specified suffixes are deleted.

ENVIRONMENT
     make uses the following environment variables, if they exist: MACHINE,
     MACHINE_ARCH, MACHINE_CPU, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, and
     PWD.  make also ignores and unsets CDPATH.

FILES
     .depend        list of dependencies
     BSDmakefile    default makefile
     makefile       default makefile if BSDmakefile does not exist
     Makefile       default makefile if makefile does not exist
     sys.mk         system makefile
     /usr/share/mk  system makefile directory
     /usr/obj       default MAKEOBJDIRPREFIX directory

SEE ALSO
     ed(1), mkdep(1), sh(1), getcwd(3), regex(3), uname(3)

     "Make -- A Tutorial", /usr/share/doc/psd/12.make/.

STANDARDS
     The make utility is compliant with the IEEE Std 1003.1-2008 (``POSIX'')
     specification, though its presence is optional.

     The flags [-BDdIjmPV] are extensions to that specification.

     Older versions of make used MAKE instead of MAKEFLAGS.  This was removed
     for POSIX compatibility.  The internal variable MAKE is set to the same
     value as .MAKE.  Support for this may be removed in the future.

     Most of the more esoteric features of make should probably be avoided for
     greater compatibility.

HISTORY
     A make command appeared in Version 7 AT&T UNIX.

BUGS
     The determination of .OBJDIR is contorted to the point of absurdity.

     If the same target is specified several times in normal dependency rules,
     make silently ignores all commands after the first non empty set of com-
     mands, e.g., in

           a:
                   @echo "Executed"
           a:
                   @echo "Bad luck"

     @echo "Bad luck" will be silently ignored.

     .TARGETS is not set to the default target when make is invoked without a
     target name and no MAIN special target exists.

     The evaluation of expression in a test is very simple-minded.  Currently,
     the only form that works is `.if ${VAR} op something'.  For instance,
     tests should be written as `.if ${VAR} == string', not the other way
     around, which doesn't work.

     For loops are expanded before tests, so a fragment such as:

           .for TMACHINE in ${SHARED_ARCHS}
           .if ${TMACHINE} == ${MACHINE}
                ...
           .endif
           .endfor

     won't work, and should be rewritten the other way around.

     When handling pre-BSD 4.4 archives, make may erroneously mark archive
     members as out of date if the archive name was truncated.

     The handling of `;' and other special characters in tests may be utterly
     bogus.  For instance, in

           A=abcd;c.c
           .if ${A:R} == "abcd;c"

     the test will never match, even though the value is correct.

     The conditional handler is incredibly lame.  Junk such as

           .if defined anything goes (A)

     will be accepted silently.

     In a .for loop, only the variable value is used; assignments will be
     evaluated later, e.g., in

           .for I in a b c d
           I:=${I:S/a/z}
           A+=$I
           .endfor

     `A' will evaluate to a b c d after the loop, not z b c d.

     ORDER is only used in parallel mode, so keep dependency ordered for se-
     quential mode!

     Distinct target names are treated separately, even though they might cor-
     respond to the same file in the file system.  This can cause excessive
     rebuilds of some targets, and bogus races in parallel mode.  This can al-
     so prevent make from finding a rule to solve a dependency if the target
     name is not exactly the same as the dependency.

     In parallel mode, -j n only limits the number of concurrent makes it
     knows about.  During recursive invocations, each level will multiply the
     number of processes by n.

     The MAKEFILE variable cannot be used reliably.  It is a compatibility
     feature and may get set to the last makefile specified, as it is set by
     System V make.

OpenBSD 4.7                    February 4, 2010                             14
