This is Info file bfd.info, produced by Makeinfo version 1.68 from the
input file /usr/src/gnu/usr.bin/binutils/bfd/doc/bfd.texinfo.

START-INFO-DIR-ENTRY
* Bfd: (bfd).                   The Binary File Descriptor library.
END-INFO-DIR-ENTRY

   This file documents the BFD library.

   Copyright (C) 1991 Free Software Foundation, Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, subject to the
terms of the GNU General Public License, which includes the provision
that the entire resulting derived work is distributed under the terms
of a permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions.


File: bfd.info,  Node: howto manager,  Prev: typedef arelent,  Up: Relocations

The howto manager
=================

When an application wants to create a relocation, but doesn't know what
the target machine might call it, it can find out by using this bit of
code.
`bfd_reloc_code_type'
.....................

*Description*
The insides of a reloc code.  The idea is that, eventually, there will
be one enumerator for every type of relocation we ever do.  Pass one of
these values to `bfd_reloc_type_lookup', and it'll return a howto
pointer.

   This does mean that the application must determine the correct
enumerator value; you can't get a howto pointer from a random set of
attributes.
Here are the possible values for `enum bfd_reloc_code_real':

 - : BFD_RELOC_64
 - : BFD_RELOC_32
 - : BFD_RELOC_26
 - : BFD_RELOC_16
 - : BFD_RELOC_14
 - : BFD_RELOC_8
     Basic absolute relocations of N bits.

 - : BFD_RELOC_64_PCREL
 - : BFD_RELOC_32_PCREL
 - : BFD_RELOC_24_PCREL
 - : BFD_RELOC_16_PCREL
 - : BFD_RELOC_12_PCREL
 - : BFD_RELOC_8_PCREL
     PC-relative relocations.  Sometimes these are relative to the
     address of the relocation itself; sometimes they are relative to
     the start of the section containing the relocation.  It depends on
     the specific target.

     The 24-bit relocation is used in some Intel 960 configurations.

 - : BFD_RELOC_32_GOT_PCREL
 - : BFD_RELOC_16_GOT_PCREL
 - : BFD_RELOC_8_GOT_PCREL
 - : BFD_RELOC_32_GOTOFF
 - : BFD_RELOC_16_GOTOFF
 - : BFD_RELOC_LO16_GOTOFF
 - : BFD_RELOC_HI16_GOTOFF
 - : BFD_RELOC_HI16_S_GOTOFF
 - : BFD_RELOC_8_GOTOFF
 - : BFD_RELOC_32_PLT_PCREL
 - : BFD_RELOC_24_PLT_PCREL
 - : BFD_RELOC_16_PLT_PCREL
 - : BFD_RELOC_8_PLT_PCREL
 - : BFD_RELOC_32_PLTOFF
 - : BFD_RELOC_16_PLTOFF
 - : BFD_RELOC_LO16_PLTOFF
 - : BFD_RELOC_HI16_PLTOFF
 - : BFD_RELOC_HI16_S_PLTOFF
 - : BFD_RELOC_8_PLTOFF
     For ELF.

 - : BFD_RELOC_68K_GLOB_DAT
 - : BFD_RELOC_68K_JMP_SLOT
 - : BFD_RELOC_68K_RELATIVE
     Relocations used by 68K ELF.

 - : BFD_RELOC_32_BASEREL
 - : BFD_RELOC_16_BASEREL
 - : BFD_RELOC_LO16_BASEREL
 - : BFD_RELOC_HI16_BASEREL
 - : BFD_RELOC_HI16_S_BASEREL
 - : BFD_RELOC_8_BASEREL
 - : BFD_RELOC_RVA
     Linkage-table relative.

 - : BFD_RELOC_8_FFnn
     Absolute 8-bit relocation, but used to form an address like 0xFFnn.

 - : BFD_RELOC_32_PCREL_S2
 - : BFD_RELOC_16_PCREL_S2
 - : BFD_RELOC_23_PCREL_S2
     These PC-relative relocations are stored as word displacements -
     i.e., byte displacements shifted right two bits.  The 30-bit word
     displacement (<<32_PCREL_S2>> - 32 bits, shifted 2) is used on the
     SPARC.  (SPARC tools generally refer to this as <<WDISP30>>.)  The
     signed 16-bit displacement is used on the MIPS, and the 23-bit
     displacement is used on the Alpha.

 - : BFD_RELOC_HI22
 - : BFD_RELOC_LO10
     High 22 bits and low 10 bits of 32-bit value, placed into lower
     bits of the target word.  These are used on the SPARC.

 - : BFD_RELOC_GPREL16
 - : BFD_RELOC_GPREL32
     For systems that allocate a Global Pointer register, these are
     displacements off that register.  These relocation types are
     handled specially, because the value the register will have is
     decided relatively late.

 - : BFD_RELOC_I960_CALLJ
     Reloc types used for i960/b.out.

 - : BFD_RELOC_NONE
 - : BFD_RELOC_SPARC_WDISP22
 - : BFD_RELOC_SPARC22
 - : BFD_RELOC_SPARC13
 - : BFD_RELOC_SPARC_GOT10
 - : BFD_RELOC_SPARC_GOT13
 - : BFD_RELOC_SPARC_GOT22
 - : BFD_RELOC_SPARC_PC10
 - : BFD_RELOC_SPARC_PC22
 - : BFD_RELOC_SPARC_WPLT30
 - : BFD_RELOC_SPARC_COPY
 - : BFD_RELOC_SPARC_GLOB_DAT
 - : BFD_RELOC_SPARC_JMP_SLOT
 - : BFD_RELOC_SPARC_RELATIVE
 - : BFD_RELOC_SPARC_UA32
     SPARC ELF relocations.  There is probably some overlap with other
     relocation types already defined.

 - : BFD_RELOC_SPARC_BASE13
 - : BFD_RELOC_SPARC_BASE22
     I think these are specific to SPARC a.out (e.g., Sun 4).

 - : BFD_RELOC_SPARC_64
 - : BFD_RELOC_SPARC_10
 - : BFD_RELOC_SPARC_11
 - : BFD_RELOC_SPARC_OLO10
 - : BFD_RELOC_SPARC_HH22
 - : BFD_RELOC_SPARC_HM10
 - : BFD_RELOC_SPARC_LM22
 - : BFD_RELOC_SPARC_PC_HH22
 - : BFD_RELOC_SPARC_PC_HM10
 - : BFD_RELOC_SPARC_PC_LM22
 - : BFD_RELOC_SPARC_WDISP16
 - : BFD_RELOC_SPARC_WDISP19
 - : BFD_RELOC_SPARC_GLOB_JMP
 - : BFD_RELOC_SPARC_7
 - : BFD_RELOC_SPARC_6
 - : BFD_RELOC_SPARC_5
     Some relocations we're using for SPARC V9 - subject to change.

 - : BFD_RELOC_ALPHA_GPDISP_HI16
     Alpha ECOFF and ELF relocations.  Some of these treat the symbol or
     "addend" in some special way.  For GPDISP_HI16 ("gpdisp")
     relocations, the symbol is ignored when writing; when reading, it
     will be the absolute section symbol.  The addend is the
     displacement in bytes of the "lda" instruction from the "ldah"
     instruction (which is at the address of this reloc).

 - : BFD_RELOC_ALPHA_GPDISP_LO16
     For GPDISP_LO16 ("ignore") relocations, the symbol is handled as
     with GPDISP_HI16 relocs.  The addend is ignored when writing the
     relocations out, and is filled in with the file's GP value on
     reading, for convenience.

 - : BFD_RELOC_ALPHA_GPDISP
     The ELF GPDISP relocation is exactly the same as the GPDISP_HI16
     relocation except that there is no accompanying GPDISP_LO16
     relocation.

 - : BFD_RELOC_ALPHA_LITERAL
 - : BFD_RELOC_ALPHA_LITERALSLEAZY
 - : BFD_RELOC_ALPHA_ELF_LITERAL
 - : BFD_RELOC_ALPHA_LITUSE
     The Alpha LITERAL/LITUSE relocs are produced by a symbol reference;
     the assembler turns it into a LDQ instruction to load the address
     of the symbol, and then fills in a register in the real
     instruction.

     The LITERAL reloc, at the LDQ instruction, refers to the .lita
     section symbol.  The addend is ignored when writing, but is filled
     in with the file's GP value on reading, for convenience, as with
     the GPDISP_LO16 reloc.

     The LITERALSLEAZY reloc is a hack to allow larger offsets (4x) than
     LITERAL.

     The ELF_LITERAL reloc is somewhere between 16_GOTOFF and
     GPDISP_LO16.  It should refer to the symbol to be referenced, as
     with 16_GOTOFF, but it generates output not based on the position
     within the .got section, but relative to the GP value chosen for
     the file during the final link stage.

     The LITUSE reloc, on the instruction using the loaded address,
     gives information to the linker that it might be able to use to
     optimize away some literal section references.  The symbol is
     ignored (read as the absolute section symbol), and the "addend"
     indicates the type of instruction using the register: 1 - "memory"
     fmt insn 2 - byte-manipulation (byte offset reg) 3 - jsr (target
     of branch)

     The GNU linker currently doesn't do any of this optimizing.

 - : BFD_RELOC_ALPHA_HINT
     The HINT relocation indicates a value that should be filled into
     the "hint" field of a jmp/jsr/ret instruction, for possible branch-
     prediction logic which may be provided on some processors.

 - : BFD_RELOC_ALPHA_LINKAGE
     The LINKAGE relocation outputs a linkage pair in the object file,
     which is filled by the linker.

 - : BFD_RELOC_MIPS_JMP
     Bits 27..2 of the relocation address shifted right 2 bits; simple
     reloc otherwise.

 - : BFD_RELOC_HI16
     High 16 bits of 32-bit value; simple reloc.

 - : BFD_RELOC_HI16_S
     High 16 bits of 32-bit value but the low 16 bits will be sign
     extended and added to form the final result.  If the low 16 bits
     form a negative number, we need to add one to the high value to
     compensate for the borrow when the low bits are added.

 - : BFD_RELOC_LO16
     Low 16 bits.

 - : BFD_RELOC_PCREL_HI16_S
     Like BFD_RELOC_HI16_S, but PC relative.

 - : BFD_RELOC_PCREL_LO16
     Like BFD_RELOC_LO16, but PC relative.

 - : BFD_RELOC_MIPS_GPREL
     Relocation relative to the global pointer.

 - : BFD_RELOC_MIPS_LITERAL
     Relocation against a MIPS literal section.

 - : BFD_RELOC_MIPS_GOT16
 - : BFD_RELOC_MIPS_CALL16
 - : BFD_RELOC_MIPS_GPREL32
 - : BFD_RELOC_MIPS_GOT_HI16
 - : BFD_RELOC_MIPS_GOT_LO16
 - : BFD_RELOC_MIPS_CALL_HI16
 - : BFD_RELOC_MIPS_CALL_LO16
     MIPS ELF relocations.

 - : BFD_RELOC_386_GOT32
 - : BFD_RELOC_386_PLT32
 - : BFD_RELOC_386_COPY
 - : BFD_RELOC_386_GLOB_DAT
 - : BFD_RELOC_386_JUMP_SLOT
 - : BFD_RELOC_386_RELATIVE
 - : BFD_RELOC_386_GOTOFF
 - : BFD_RELOC_386_GOTPC
     i386/elf relocations

 - : BFD_RELOC_NS32K_IMM_8
 - : BFD_RELOC_NS32K_IMM_16
 - : BFD_RELOC_NS32K_IMM_32
 - : BFD_RELOC_NS32K_IMM_8_PCREL
 - : BFD_RELOC_NS32K_IMM_16_PCREL
 - : BFD_RELOC_NS32K_IMM_32_PCREL
 - : BFD_RELOC_NS32K_DISP_8
 - : BFD_RELOC_NS32K_DISP_16
 - : BFD_RELOC_NS32K_DISP_32
 - : BFD_RELOC_NS32K_DISP_8_PCREL
 - : BFD_RELOC_NS32K_DISP_16_PCREL
 - : BFD_RELOC_NS32K_DISP_32_PCREL
     ns32k relocations

 - : BFD_RELOC_PPC_B26
 - : BFD_RELOC_PPC_BA26
 - : BFD_RELOC_PPC_TOC16
 - : BFD_RELOC_PPC_B16
 - : BFD_RELOC_PPC_B16_BRTAKEN
 - : BFD_RELOC_PPC_B16_BRNTAKEN
 - : BFD_RELOC_PPC_BA16
 - : BFD_RELOC_PPC_BA16_BRTAKEN
 - : BFD_RELOC_PPC_BA16_BRNTAKEN
 - : BFD_RELOC_PPC_COPY
 - : BFD_RELOC_PPC_GLOB_DAT
 - : BFD_RELOC_PPC_JMP_SLOT
 - : BFD_RELOC_PPC_RELATIVE
 - : BFD_RELOC_PPC_LOCAL24PC
 - : BFD_RELOC_PPC_EMB_NADDR32
 - : BFD_RELOC_PPC_EMB_NADDR16
 - : BFD_RELOC_PPC_EMB_NADDR16_LO
 - : BFD_RELOC_PPC_EMB_NADDR16_HI
 - : BFD_RELOC_PPC_EMB_NADDR16_HA
 - : BFD_RELOC_PPC_EMB_SDAI16
 - : BFD_RELOC_PPC_EMB_SDA2I16
 - : BFD_RELOC_PPC_EMB_SDA2REL
 - : BFD_RELOC_PPC_EMB_SDA21
 - : BFD_RELOC_PPC_EMB_MRKREF
 - : BFD_RELOC_PPC_EMB_RELSEC16
 - : BFD_RELOC_PPC_EMB_RELST_LO
 - : BFD_RELOC_PPC_EMB_RELST_HI
 - : BFD_RELOC_PPC_EMB_RELST_HA
 - : BFD_RELOC_PPC_EMB_BIT_FLD
 - : BFD_RELOC_PPC_EMB_RELSDA
     Power(rs6000) and PowerPC relocations.

 - : BFD_RELOC_CTOR
     The type of reloc used to build a contructor table - at the moment
     probably a 32 bit wide absolute relocation, but the target can
     choose.  It generally does map to one of the other relocation
     types.

 - : BFD_RELOC_ARM_PCREL_BRANCH
     ARM 26 bit pc-relative branch.  The lowest two bits must be zero
     and are not stored in the instruction.

 - : BFD_RELOC_ARM_IMMEDIATE
 - : BFD_RELOC_ARM_OFFSET_IMM
 - : BFD_RELOC_ARM_SHIFT_IMM
 - : BFD_RELOC_ARM_SWI
 - : BFD_RELOC_ARM_MULTI
 - : BFD_RELOC_ARM_CP_OFF_IMM
 - : BFD_RELOC_ARM_ADR_IMM
 - : BFD_RELOC_ARM_LDR_IMM
 - : BFD_RELOC_ARM_LITERAL
 - : BFD_RELOC_ARM_IN_POOL
 - : BFD_RELOC_ARM_OFFSET_IMM8
 - : BFD_RELOC_ARM_HWLITERAL
 - : BFD_RELOC_ARM_THUMB_ADD
 - : BFD_RELOC_ARM_THUMB_IMM
 - : BFD_RELOC_ARM_THUMB_SHIFT
 - : BFD_RELOC_ARM_THUMB_OFFSET
     These relocs are only used within the ARM assembler.  They are not
     (at present) written to any object files.

 - : BFD_RELOC_SH_PCDISP8BY2
 - : BFD_RELOC_SH_PCDISP12BY2
 - : BFD_RELOC_SH_IMM4
 - : BFD_RELOC_SH_IMM4BY2
 - : BFD_RELOC_SH_IMM4BY4
 - : BFD_RELOC_SH_IMM8
 - : BFD_RELOC_SH_IMM8BY2
 - : BFD_RELOC_SH_IMM8BY4
 - : BFD_RELOC_SH_PCRELIMM8BY2
 - : BFD_RELOC_SH_PCRELIMM8BY4
 - : BFD_RELOC_SH_SWITCH16
 - : BFD_RELOC_SH_SWITCH32
 - : BFD_RELOC_SH_USES
 - : BFD_RELOC_SH_COUNT
 - : BFD_RELOC_SH_ALIGN
 - : BFD_RELOC_SH_CODE
 - : BFD_RELOC_SH_DATA
 - : BFD_RELOC_SH_LABEL
     Hitachi SH relocs.  Not all of these appear in object files.
   .
     typedef enum bfd_reloc_code_real bfd_reloc_code_real_type;

`bfd_reloc_type_lookup'
.......................

   *Synopsis*
     reloc_howto_type *
     bfd_reloc_type_lookup (bfd *abfd, bfd_reloc_code_real_type code);
   *Description*
Return a pointer to a howto structure which, when invoked, will perform
the relocation CODE on data from the architecture noted.
`bfd_default_reloc_type_lookup'
...............................

*Synopsis*
     reloc_howto_type *bfd_default_reloc_type_lookup
        (bfd *abfd, bfd_reloc_code_real_type  code);
   *Description*
Provides a default relocation lookup routine for any architecture.
`bfd_get_reloc_code_name'
.........................

*Synopsis*
     const char *bfd_get_reloc_code_name (bfd_reloc_code_real_type code);
   *Description*
Provides a printable name for the supplied relocation code.  Useful
mainly for printing error messages.
`bfd_generic_relax_section'
...........................

*Synopsis*
     boolean bfd_generic_relax_section
        (bfd *abfd,
         asection *section,
         struct bfd_link_info *,
         boolean *);
   *Description*
Provides default handling for relaxing for back ends which don't do
relaxing - i.e., does nothing.
`bfd_generic_get_relocated_section_contents'
............................................

*Synopsis*
     bfd_byte *
     bfd_generic_get_relocated_section_contents (bfd *abfd,
         struct bfd_link_info *link_info,
         struct bfd_link_order *link_order,
         bfd_byte *data,
         boolean relocateable,
         asymbol **symbols);
   *Description*
Provides default handling of relocation effort for back ends which
can't be bothered to do it efficiently.

File: bfd.info,  Node: Core Files,  Next: Targets,  Prev: Relocations,  Up: BFD front end

Core files
==========

*Description*
These are functions pertaining to core files.
`bfd_core_file_failing_command'
...............................

*Synopsis*
     CONST char *bfd_core_file_failing_command(bfd *abfd);
   *Description*
Return a read-only string explaining which program was running when it
failed and produced the core file ABFD.
`bfd_core_file_failing_signal'
..............................

*Synopsis*
     int bfd_core_file_failing_signal(bfd *abfd);
   *Description*
Returns the signal number which caused the core dump which generated
the file the BFD ABFD is attached to.
`core_file_matches_executable_p'
................................

*Synopsis*
     boolean core_file_matches_executable_p
        (bfd *core_bfd, bfd *exec_bfd);
   *Description*
Return `true' if the core file attached to CORE_BFD was generated by a
run of the executable file attached to EXEC_BFD, `false' otherwise.

File: bfd.info,  Node: Targets,  Next: Architectures,  Prev: Core Files,  Up: BFD front end

Targets
=======

*Description*
Each port of BFD to a different machine requries the creation of a
target back end. All the back end provides to the root part of BFD is a
structure containing pointers to functions which perform certain low
level operations on files. BFD translates the applications's requests
through a pointer into calls to the back end routines.

   When a file is opened with `bfd_openr', its format and target are
unknown. BFD uses various mechanisms to determine how to interpret the
file. The operations performed are:

   * Create a BFD by calling the internal routine `_bfd_new_bfd', then
     call `bfd_find_target' with the target string supplied to
     `bfd_openr' and the new BFD pointer.

   * If a null target string was provided to `bfd_find_target', look up
     the environment variable `GNUTARGET' and use that as the target
     string.

   * If the target string is still `NULL', or the target string is
     `default', then use the first item in the target vector as the
     target type, and set `target_defaulted' in the BFD to cause
     `bfd_check_format' to loop through all the targets.  *Note
     bfd_target::.  *Note Formats::.

   * Otherwise, inspect the elements in the target vector one by one,
     until a match on target name is found. When found, use it.

   * Otherwise return the error `bfd_error_invalid_target' to
     `bfd_openr'.

   * `bfd_openr' attempts to open the file using `bfd_open_file', and
     returns the BFD.  Once the BFD has been opened and the target
selected, the file format may be determined. This is done by calling
`bfd_check_format' on the BFD with a suggested format.  If
`target_defaulted' has been set, each possible target type is tried to
see if it recognizes the specified format.  `bfd_check_format' returns
`true' when the caller guesses right.

* Menu:

* bfd_target::


File: bfd.info,  Node: bfd_target,  Prev: Targets,  Up: Targets

bfd_target
----------

*Description*
This structure contains everything that BFD knows about a target. It
includes things like its byte order, name, and which routines to call
to do various operations.

   Every BFD points to a target structure with its `xvec' member.

   The macros below are used to dispatch to functions through the
`bfd_target' vector. They are used in a number of macros further down
in `bfd.h', and are also used when calling various routines by hand
inside the BFD implementation.  The ARGLIST argument must be
parenthesized; it contains all the arguments to the called function.

   They make the documentation (more) unpleasant to read, so if someone
wants to fix this and not break the above, please do.
     #define BFD_SEND(bfd, message, arglist) \
                    ((*((bfd)->xvec->message)) arglist)
     
     #ifdef DEBUG_BFD_SEND
     #undef BFD_SEND
     #define BFD_SEND(bfd, message, arglist) \
       (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \
         ((*((bfd)->xvec->message)) arglist) : \
         (bfd_assert (__FILE__,__LINE__), NULL))
     #endif
   For operations which index on the BFD format:
     #define BFD_SEND_FMT(bfd, message, arglist) \
                 (((bfd)->xvec->message[(int)((bfd)->format)]) arglist)
     
     #ifdef DEBUG_BFD_SEND
     #undef BFD_SEND_FMT
     #define BFD_SEND_FMT(bfd, message, arglist) \
       (((bfd) && (bfd)->xvec && (bfd)->xvec->message) ? \
        (((bfd)->xvec->message[(int)((bfd)->format)]) arglist) : \
        (bfd_assert (__FILE__,__LINE__), NULL))
     #endif
   This is the structure which defines the type of BFD this is.  The
`xvec' member of the struct `bfd' itself points here.  Each module that
implements access to a different target under BFD, defines one of these.

   FIXME, these names should be rationalised with the names of the
entry points which call them. Too bad we can't have one macro to define
them both!
     enum bfd_flavour {
       bfd_target_unknown_flavour,
       bfd_target_aout_flavour,
       bfd_target_coff_flavour,
       bfd_target_ecoff_flavour,
       bfd_target_elf_flavour,
       bfd_target_ieee_flavour,
       bfd_target_nlm_flavour,
       bfd_target_oasys_flavour,
       bfd_target_tekhex_flavour,
       bfd_target_srec_flavour,
       bfd_target_ihex_flavour,
       bfd_target_som_flavour,
       bfd_target_os9k_flavour,
       bfd_target_versados_flavour,
       bfd_target_msdos_flavour,
       bfd_target_evax_flavour
     };
     
     enum bfd_endian { BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN };
     
      /* Forward declaration.  */
     typedef struct bfd_link_info _bfd_link_info;
     
     typedef struct bfd_target
     {
   Identifies the kind of target, e.g., SunOS4, Ultrix, etc.
       char *name;
   The "flavour" of a back end is a general indication about the
contents of a file.
       enum bfd_flavour flavour;
   The order of bytes within the data area of a file.
       enum bfd_endian byteorder;
   The order of bytes within the header parts of a file.
       enum bfd_endian header_byteorder;
   A mask of all the flags which an executable may have set - from the
set `BFD_NO_FLAGS', `HAS_RELOC', ...`D_PAGED'.
       flagword object_flags;
   A mask of all the flags which a section may have set - from the set
`SEC_NO_FLAGS', `SEC_ALLOC', ...`SET_NEVER_LOAD'.
       flagword section_flags;
   The character normally found at the front of a symbol (if any),
perhaps `_'.
       char symbol_leading_char;
   The pad character for file names within an archive header.
       char ar_pad_char;
   The maximum number of characters in an archive header.
       unsigned short ar_max_namelen;
   Entries for byte swapping for data. These are different from the
other entry points, since they don't take a BFD asthe first argument.
Certain other handlers could do the same.
       bfd_vma      (*bfd_getx64) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_getx_signed_64) PARAMS ((const bfd_byte *));
       void         (*bfd_putx64) PARAMS ((bfd_vma, bfd_byte *));
       bfd_vma      (*bfd_getx32) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_getx_signed_32) PARAMS ((const bfd_byte *));
       void         (*bfd_putx32) PARAMS ((bfd_vma, bfd_byte *));
       bfd_vma      (*bfd_getx16) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_getx_signed_16) PARAMS ((const bfd_byte *));
       void         (*bfd_putx16) PARAMS ((bfd_vma, bfd_byte *));
   Byte swapping for the headers
       bfd_vma      (*bfd_h_getx64) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_h_getx_signed_64) PARAMS ((const bfd_byte *));
       void         (*bfd_h_putx64) PARAMS ((bfd_vma, bfd_byte *));
       bfd_vma      (*bfd_h_getx32) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_h_getx_signed_32) PARAMS ((const bfd_byte *));
       void         (*bfd_h_putx32) PARAMS ((bfd_vma, bfd_byte *));
       bfd_vma      (*bfd_h_getx16) PARAMS ((const bfd_byte *));
       bfd_signed_vma (*bfd_h_getx_signed_16) PARAMS ((const bfd_byte *));
       void         (*bfd_h_putx16) PARAMS ((bfd_vma, bfd_byte *));
   Format dependent routines: these are vectors of entry points within
the target vector structure, one for each format to check.

   Check the format of a file being read.  Return a `bfd_target *' or
zero.
       const struct bfd_target *(*_bfd_check_format[bfd_type_end]) PARAMS ((bfd *));
   Set the format of a file being written.
       boolean             (*_bfd_set_format[bfd_type_end]) PARAMS ((bfd *));
   Write cached information into a file being written, at `bfd_close'.
       boolean             (*_bfd_write_contents[bfd_type_end]) PARAMS ((bfd *));
   The general target vector.

        /* Generic entry points.  */
     #define BFD_JUMP_TABLE_GENERIC(NAME)\
     CAT(NAME,_close_and_cleanup),\
     CAT(NAME,_bfd_free_cached_info),\
     CAT(NAME,_new_section_hook),\
     CAT(NAME,_get_section_contents),\
     CAT(NAME,_get_section_contents_in_window)
     
        /* Called when the BFD is being closed to do any necessary cleanup.  */
       boolean       (*_close_and_cleanup) PARAMS ((bfd *));
        /* Ask the BFD to free all cached information.  */
       boolean (*_bfd_free_cached_info) PARAMS ((bfd *));
        /* Called when a new section is created.  */
       boolean       (*_new_section_hook) PARAMS ((bfd *, sec_ptr));
        /* Read the contents of a section.  */
       boolean       (*_bfd_get_section_contents) PARAMS ((bfd *, sec_ptr, PTR,
                                                 file_ptr, bfd_size_type));
       boolean       (*_bfd_get_section_contents_in_window)
                               PARAMS ((bfd *, sec_ptr, bfd_window *,
                                        file_ptr, bfd_size_type));
     
        /* Entry points to copy private data.  */
     #define BFD_JUMP_TABLE_COPY(NAME)\
     CAT(NAME,_bfd_copy_private_bfd_data),\
     CAT(NAME,_bfd_merge_private_bfd_data),\
     CAT(NAME,_bfd_copy_private_section_data),\
     CAT(NAME,_bfd_copy_private_symbol_data),\
     CAT(NAME,_bfd_set_private_flags),\
     CAT(NAME,_bfd_print_private_bfd_data)\
        /* Called to copy BFD general private data from one object file
          to another.  */
       boolean	 (*_bfd_copy_private_bfd_data) PARAMS ((bfd *, bfd *));
        /* Called to merge BFD general private data from one object file
          to a common output file when linking.  */
       boolean	 (*_bfd_merge_private_bfd_data) PARAMS ((bfd *, bfd *));
        /* Called to copy BFD private section data from one object file
          to another.  */
       boolean       (*_bfd_copy_private_section_data) PARAMS ((bfd *, sec_ptr,
                                                            bfd *, sec_ptr));
        /* Called to copy BFD private symbol data from one symbol
          to another.  */
       boolean       (*_bfd_copy_private_symbol_data) PARAMS ((bfd *, asymbol *,
     							   bfd *, asymbol *));
        /* Called to set private backend flags */
       boolean	 (*_bfd_set_private_flags) PARAMS ((bfd *, flagword));
     
        /* Called to print private BFD data */
       boolean       (*_bfd_print_private_bfd_data) PARAMS ((bfd *, PTR));
     
        /* Core file entry points.  */
     #define BFD_JUMP_TABLE_CORE(NAME)\
     CAT(NAME,_core_file_failing_command),\
     CAT(NAME,_core_file_failing_signal),\
     CAT(NAME,_core_file_matches_executable_p)
       char *   (*_core_file_failing_command) PARAMS ((bfd *));
       int      (*_core_file_failing_signal) PARAMS ((bfd *));
       boolean  (*_core_file_matches_executable_p) PARAMS ((bfd *, bfd *));
     
        /* Archive entry points.  */
     #define BFD_JUMP_TABLE_ARCHIVE(NAME)\
     CAT(NAME,_slurp_armap),\
     CAT(NAME,_slurp_extended_name_table),\
     CAT(NAME,_construct_extended_name_table),\
     CAT(NAME,_truncate_arname),\
     CAT(NAME,_write_armap),\
     CAT(NAME,_read_ar_hdr),\
     CAT(NAME,_openr_next_archived_file),\
     CAT(NAME,_get_elt_at_index),\
     CAT(NAME,_generic_stat_arch_elt),\
     CAT(NAME,_update_armap_timestamp)
       boolean  (*_bfd_slurp_armap) PARAMS ((bfd *));
       boolean  (*_bfd_slurp_extended_name_table) PARAMS ((bfd *));
       boolean  (*_bfd_construct_extended_name_table)
                  PARAMS ((bfd *, char **, bfd_size_type *, const char **));
       void     (*_bfd_truncate_arname) PARAMS ((bfd *, CONST char *, char *));
       boolean  (*write_armap) PARAMS ((bfd *arch,
                                   unsigned int elength,
                                   struct orl *map,
                                   unsigned int orl_count,
                                   int stridx));
       PTR (*_bfd_read_ar_hdr_fn) PARAMS ((bfd *));
       bfd *    (*openr_next_archived_file) PARAMS ((bfd *arch, bfd *prev));
     #define bfd_get_elt_at_index(b,i) BFD_SEND(b, _bfd_get_elt_at_index, (b,i))
       bfd *    (*_bfd_get_elt_at_index) PARAMS ((bfd *, symindex));
       int      (*_bfd_stat_arch_elt) PARAMS ((bfd *, struct stat *));
       boolean  (*_bfd_update_armap_timestamp) PARAMS ((bfd *));
     
        /* Entry points used for symbols.  */
     #define BFD_JUMP_TABLE_SYMBOLS(NAME)\
     CAT(NAME,_get_symtab_upper_bound),\
     CAT(NAME,_get_symtab),\
     CAT(NAME,_make_empty_symbol),\
     CAT(NAME,_print_symbol),\
     CAT(NAME,_get_symbol_info),\
     CAT(NAME,_bfd_is_local_label),\
     CAT(NAME,_get_lineno),\
     CAT(NAME,_find_nearest_line),\
     CAT(NAME,_bfd_make_debug_symbol),\
     CAT(NAME,_read_minisymbols),\
     CAT(NAME,_minisymbol_to_symbol)
       long  (*_bfd_get_symtab_upper_bound) PARAMS ((bfd *));
       long  (*_bfd_canonicalize_symtab) PARAMS ((bfd *,
                                                  struct symbol_cache_entry **));
       struct symbol_cache_entry  *
                     (*_bfd_make_empty_symbol) PARAMS ((bfd *));
       void          (*_bfd_print_symbol) PARAMS ((bfd *, PTR,
                                           struct symbol_cache_entry *,
                                           bfd_print_symbol_type));
     #define bfd_print_symbol(b,p,s,e) BFD_SEND(b, _bfd_print_symbol, (b,p,s,e))
       void          (*_bfd_get_symbol_info) PARAMS ((bfd *,
                                           struct symbol_cache_entry *,
                                           symbol_info *));
     #define bfd_get_symbol_info(b,p,e) BFD_SEND(b, _bfd_get_symbol_info, (b,p,e))
       boolean	 (*_bfd_is_local_label) PARAMS ((bfd *, asymbol *));
     
       alent *    (*_get_lineno) PARAMS ((bfd *, struct symbol_cache_entry *));
       boolean    (*_bfd_find_nearest_line) PARAMS ((bfd *abfd,
                         struct sec *section, struct symbol_cache_entry **symbols,
                         bfd_vma offset, CONST char **file, CONST char **func,
                         unsigned int *line));
       /* Back-door to allow format-aware applications to create debug symbols
         while using BFD for everything else.  Currently used by the assembler
         when creating COFF files.  */
       asymbol *  (*_bfd_make_debug_symbol) PARAMS ((
            bfd *abfd,
            void *ptr,
            unsigned long size));
     #define bfd_read_minisymbols(b, d, m, s) \
       BFD_SEND (b, _read_minisymbols, (b, d, m, s))
       long  (*_read_minisymbols) PARAMS ((bfd *, boolean, PTR *,
                                           unsigned int *));
     #define bfd_minisymbol_to_symbol(b, d, m, f) \
       BFD_SEND (b, _minisymbol_to_symbol, (b, d, m, f))
       asymbol *(*_minisymbol_to_symbol) PARAMS ((bfd *, boolean, const PTR,
                                                  asymbol *));
     
        /* Routines for relocs.  */
     #define BFD_JUMP_TABLE_RELOCS(NAME)\
     CAT(NAME,_get_reloc_upper_bound),\
     CAT(NAME,_canonicalize_reloc),\
     CAT(NAME,_bfd_reloc_type_lookup)
       long  (*_get_reloc_upper_bound) PARAMS ((bfd *, sec_ptr));
       long  (*_bfd_canonicalize_reloc) PARAMS ((bfd *, sec_ptr, arelent **,
                                                 struct symbol_cache_entry **));
        /* See documentation on reloc types.  */
       reloc_howto_type *
            (*reloc_type_lookup) PARAMS ((bfd *abfd,
                                          bfd_reloc_code_real_type code));
     
        /* Routines used when writing an object file.  */
     #define BFD_JUMP_TABLE_WRITE(NAME)\
     CAT(NAME,_set_arch_mach),\
     CAT(NAME,_set_section_contents)
       boolean    (*_bfd_set_arch_mach) PARAMS ((bfd *, enum bfd_architecture,
                         unsigned long));
       boolean       (*_bfd_set_section_contents) PARAMS ((bfd *, sec_ptr, PTR,
                                                 file_ptr, bfd_size_type));
     
        /* Routines used by the linker.  */
     #define BFD_JUMP_TABLE_LINK(NAME)\
     CAT(NAME,_sizeof_headers),\
     CAT(NAME,_bfd_get_relocated_section_contents),\
     CAT(NAME,_bfd_relax_section),\
     CAT(NAME,_bfd_link_hash_table_create),\
     CAT(NAME,_bfd_link_add_symbols),\
     CAT(NAME,_bfd_final_link),\
     CAT(NAME,_bfd_link_split_section)
       int        (*_bfd_sizeof_headers) PARAMS ((bfd *, boolean));
       bfd_byte * (*_bfd_get_relocated_section_contents) PARAMS ((bfd *,
                         struct bfd_link_info *, struct bfd_link_order *,
                         bfd_byte *data, boolean relocateable,
                         struct symbol_cache_entry **));
     
       boolean    (*_bfd_relax_section) PARAMS ((bfd *, struct sec *,
                         struct bfd_link_info *, boolean *again));
     
        /* Create a hash table for the linker.  Different backends store
          different information in this table.  */
       struct bfd_link_hash_table *(*_bfd_link_hash_table_create) PARAMS ((bfd *));
     
        /* Add symbols from this object file into the hash table.  */
       boolean (*_bfd_link_add_symbols) PARAMS ((bfd *, struct bfd_link_info *));
     
        /* Do a link based on the link_order structures attached to each
          section of the BFD.  */
       boolean (*_bfd_final_link) PARAMS ((bfd *, struct bfd_link_info *));
     
        /* Should this section be split up into smaller pieces during linking.  */
       boolean (*_bfd_link_split_section) PARAMS ((bfd *, struct sec *));
     
       /* Routines to handle dynamic symbols and relocs.  */
     #define BFD_JUMP_TABLE_DYNAMIC(NAME)\
     CAT(NAME,_get_dynamic_symtab_upper_bound),\
     CAT(NAME,_canonicalize_dynamic_symtab),\
     CAT(NAME,_get_dynamic_reloc_upper_bound),\
     CAT(NAME,_canonicalize_dynamic_reloc)
        /* Get the amount of memory required to hold the dynamic symbols. */
       long  (*_bfd_get_dynamic_symtab_upper_bound) PARAMS ((bfd *));
        /* Read in the dynamic symbols.  */
       long  (*_bfd_canonicalize_dynamic_symtab)
         PARAMS ((bfd *, struct symbol_cache_entry **));
        /* Get the amount of memory required to hold the dynamic relocs.  */
       long  (*_bfd_get_dynamic_reloc_upper_bound) PARAMS ((bfd *));
        /* Read in the dynamic relocs.  */
       long  (*_bfd_canonicalize_dynamic_reloc)
         PARAMS ((bfd *, arelent **, struct symbol_cache_entry **));
   Data for use by back-end routines, which isn't generic enough to
belong in this structure.
      PTR backend_data;
     } bfd_target;

`bfd_find_target'
.................

*Synopsis*
     const bfd_target *bfd_find_target(CONST char *target_name, bfd *abfd);
   *Description*
Return a pointer to the transfer vector for the object target named
TARGET_NAME.  If TARGET_NAME is `NULL', choose the one in the
environment variable `GNUTARGET'; if that is null or not defined, then
choose the first entry in the target list.  Passing in the string
"default" or setting the environment variable to "default" will cause
the first entry in the target list to be returned, and
"target_defaulted" will be set in the BFD.  This causes
`bfd_check_format' to loop over all the targets to find the one that
matches the file being read.
`bfd_target_list'
.................

*Synopsis*
     const char **bfd_target_list(void);
   *Description*
Return a freshly malloced NULL-terminated vector of the names of all
the valid BFD targets. Do not modify the names.

File: bfd.info,  Node: Architectures,  Next: Opening and Closing,  Prev: Targets,  Up: BFD front end

Architectures
=============

BFD keeps one atom in a BFD describing the architecture of the data
attached to the BFD: a pointer to a `bfd_arch_info_type'.

   Pointers to structures can be requested independently of a BFD so
that an architecture's information can be interrogated without access
to an open BFD.

   The architecture information is provided by each architecture
package.  The set of default architectures is selected by the macro
`SELECT_ARCHITECTURES'.  This is normally set up in the
`config/TARGET.mt' file of your choice.  If the name is not defined,
then all the architectures supported are included.

   When BFD starts up, all the architectures are called with an
initialize method.  It is up to the architecture back end to insert as
many items into the list of architectures as it wants to; generally
this would be one for each machine and one for the default case (an
item with a machine field of 0).

   BFD's idea of an architecture is implemented in	`archures.c'.
bfd_architecture
----------------

*Description*
This enum gives the object file's CPU architecture, in a global
sense--i.e., what processor family does it belong to?  Another field
indicates which processor within the family is in use.  The machine
gives a number which distinguishes different versions of the
architecture, containing, for example, 2 and 3 for Intel i960 KA and
i960 KB, and 68020 and 68030 for Motorola 68020 and 68030.
     enum bfd_architecture
     {
       bfd_arch_unknown,    /* File arch not known */
       bfd_arch_obscure,    /* Arch known, not one of these */
       bfd_arch_m68k,       /* Motorola 68xxx */
       bfd_arch_vax,        /* DEC Vax */
       bfd_arch_i960,       /* Intel 960 */
          /* The order of the following is important.
            lower number indicates a machine type that
            only accepts a subset of the instructions
            available to machines with higher numbers.
            The exception is the "ca", which is
            incompatible with all other machines except
            "core". */
     
     #define bfd_mach_i960_core      1
     #define bfd_mach_i960_ka_sa     2
     #define bfd_mach_i960_kb_sb     3
     #define bfd_mach_i960_mc        4
     #define bfd_mach_i960_xa        5
     #define bfd_mach_i960_ca        6
     #define bfd_mach_i960_jx	 7
     #define bfd_mach_i960_hx        8
     
       bfd_arch_a29k,       /* AMD 29000 */
       bfd_arch_sparc,      /* SPARC */
     #define bfd_mach_sparc			1
      /* The difference between v8plus and v9 is that v9 is a true 64 bit env.  */
     #define bfd_mach_sparc_sparclet	2
     #define bfd_mach_sparc_sparclite	3
     #define bfd_mach_sparc_v8plus		4
     #define bfd_mach_sparc_v8plusa		5  /* with ultrasparc add'ns */
     #define bfd_mach_sparc_v9		6
     #define bfd_mach_sparc_v9a		7  /* with ultrasparc add'ns */
      /* Nonzero if MACH has the v9 instruction set.  */
     #define bfd_mach_sparc_v9_p(mach) \
       ((mach) >= bfd_mach_sparc_v8plus && (mach) <= bfd_mach_sparc_v9a)
       bfd_arch_mips,       /* MIPS Rxxxx */
       bfd_arch_i386,       /* Intel 386 */
     #define bfd_mach_i386_i386 0
     #define bfd_mach_i386_i8086 1
       bfd_arch_we32k,      /* AT&T WE32xxx */
       bfd_arch_tahoe,      /* CCI/Harris Tahoe */
       bfd_arch_i860,       /* Intel 860 */
       bfd_arch_romp,       /* IBM ROMP PC/RT */
       bfd_arch_alliant,    /* Alliant */
       bfd_arch_convex,     /* Convex */
       bfd_arch_m88k,       /* Motorola 88xxx */
       bfd_arch_pyramid,    /* Pyramid Technology */
       bfd_arch_h8300,      /* Hitachi H8/300 */
     #define bfd_mach_h8300   1
     #define bfd_mach_h8300h  2
     #define bfd_mach_h8300s  3
       bfd_arch_powerpc,    /* PowerPC */
       bfd_arch_rs6000,     /* IBM RS/6000 */
       bfd_arch_hppa,       /* HP PA RISC */
       bfd_arch_z8k,        /* Zilog Z8000 */
     #define bfd_mach_z8001		1
     #define bfd_mach_z8002		2
       bfd_arch_h8500,      /* Hitachi H8/500 */
       bfd_arch_sh,         /* Hitachi SH */
       bfd_arch_alpha,      /* Dec Alpha */
       bfd_arch_arm,        /* Advanced Risc Machines ARM */
       bfd_arch_ns32k,      /* National Semiconductors ns32000 */
       bfd_arch_w65,        /* WDC 65816 */
       bfd_arch_mn10200,    /* Matsushita MN10200 */
       bfd_arch_mn10300,    /* Matsushita MN10300 */
       bfd_arch_last
       };

bfd_arch_info
-------------

*Description*
This structure contains information on architectures for use within BFD.

     typedef struct bfd_arch_info
     {
       int bits_per_word;
       int bits_per_address;
       int bits_per_byte;
       enum bfd_architecture arch;
       unsigned long mach;
       const char *arch_name;
       const char *printable_name;
       unsigned int section_align_power;
       /* true if this is the default machine for the architecture */
       boolean the_default;
       const struct bfd_arch_info * (*compatible)
     	PARAMS ((const struct bfd_arch_info *a,
     	         const struct bfd_arch_info *b));
     
       boolean (*scan) PARAMS ((const struct bfd_arch_info *, const char *));
     
       const struct bfd_arch_info *next;
     } bfd_arch_info_type;

`bfd_printable_name'
....................

*Synopsis*
     const char *bfd_printable_name(bfd *abfd);
   *Description*
Return a printable string representing the architecture and machine
from the pointer to the architecture info structure.
`bfd_scan_arch'
...............

*Synopsis*
     const bfd_arch_info_type *bfd_scan_arch(const char *string);
   *Description*
Figure out if BFD supports any cpu which could be described with the
name STRING.  Return a pointer to an `arch_info' structure if a machine
is found, otherwise NULL.
`bfd_arch_get_compatible'
.........................

*Synopsis*
     const bfd_arch_info_type *bfd_arch_get_compatible(
         const bfd *abfd,
         const bfd *bbfd);
   *Description*
Determine whether two BFDs' architectures and machine types are
compatible.  Calculates the lowest common denominator between the two
architectures and machine types implied by the BFDs and returns a
pointer to an `arch_info' structure describing the compatible machine.
`bfd_default_arch_struct'
.........................

*Description*
The `bfd_default_arch_struct' is an item of `bfd_arch_info_type' which
has been initialized to a fairly generic state.  A BFD starts life by
pointing to this structure, until the correct back end has determined
the real architecture of the file.
     extern const bfd_arch_info_type bfd_default_arch_struct;

`bfd_set_arch_info'
...................

*Synopsis*
     void bfd_set_arch_info(bfd *abfd, const bfd_arch_info_type *arg);
   *Description*
Set the architecture info of ABFD to ARG.
`bfd_default_set_arch_mach'
...........................

*Synopsis*
     boolean bfd_default_set_arch_mach(bfd *abfd,
         enum bfd_architecture arch,
         unsigned long mach);
   *Description*
Set the architecture and machine type in BFD ABFD to ARCH and MACH.
Find the correct pointer to a structure and insert it into the
`arch_info' pointer.
`bfd_get_arch'
..............

*Synopsis*
     enum bfd_architecture bfd_get_arch(bfd *abfd);
   *Description*
Return the enumerated type which describes the BFD ABFD's architecture.
`bfd_get_mach'
..............

*Synopsis*
     unsigned long bfd_get_mach(bfd *abfd);
   *Description*
Return the long type which describes the BFD ABFD's machine.
`bfd_arch_bits_per_byte'
........................

*Synopsis*
     unsigned int bfd_arch_bits_per_byte(bfd *abfd);
   *Description*
Return the number of bits in one of the BFD ABFD's architecture's bytes.
`bfd_arch_bits_per_address'
...........................

*Synopsis*
     unsigned int bfd_arch_bits_per_address(bfd *abfd);
   *Description*
Return the number of bits in one of the BFD ABFD's architecture's
addresses.
`bfd_default_compatible'
........................

*Synopsis*
     const bfd_arch_info_type *bfd_default_compatible
        (const bfd_arch_info_type *a,
         const bfd_arch_info_type *b);
   *Description*
The default function for testing for compatibility.
`bfd_default_scan'
..................

*Synopsis*
     boolean bfd_default_scan(const struct bfd_arch_info *info, const char *string);
   *Description*
The default function for working out whether this is an architecture
hit and a machine hit.
`bfd_get_arch_info'
...................

*Synopsis*
     const bfd_arch_info_type * bfd_get_arch_info(bfd *abfd);
   *Description*
Return the architecture info struct in ABFD.
`bfd_lookup_arch'
.................

*Synopsis*
     const bfd_arch_info_type *bfd_lookup_arch
        (enum bfd_architecture
         arch,
         unsigned long machine);
   *Description*
Look for the architecure info structure which matches the arguments
ARCH and MACHINE. A machine of 0 matches the machine/architecture
structure which marks itself as the default.
`bfd_printable_arch_mach'
.........................

*Synopsis*
     const char *bfd_printable_arch_mach
        (enum bfd_architecture arch, unsigned long machine);
   *Description*
Return a printable string representing the architecture and machine
type.

   This routine is depreciated.

File: bfd.info,  Node: Opening and Closing,  Next: Internal,  Prev: Architectures,  Up: BFD front end

Opening and closing BFDs
========================

`bfd_openr'
...........

*Synopsis*
     bfd *bfd_openr(CONST char *filename, CONST char *target);
   *Description*
Open the file FILENAME (using `fopen') with the target TARGET.  Return
a pointer to the created BFD.

   Calls `bfd_find_target', so TARGET is interpreted as by that
function.

   If `NULL' is returned then an error has occured.   Possible errors
are `bfd_error_no_memory', `bfd_error_invalid_target' or `system_call'
error.
`bfd_fdopenr'
.............

*Synopsis*
     bfd *bfd_fdopenr(CONST char *filename, CONST char *target, int fd);
   *Description*
`bfd_fdopenr' is to `bfd_fopenr' much like `fdopen' is to `fopen'.  It
opens a BFD on a file already described by the FD supplied.

   When the file is later `bfd_close'd, the file descriptor will be
closed.

   If the caller desires that this file descriptor be cached by BFD
(opened as needed, closed as needed to free descriptors for other
opens), with the supplied FD used as an initial file descriptor (but
subject to closure at any time), call bfd_set_cacheable(bfd, 1) on the
returned BFD.  The default is to assume no cacheing; the file
descriptor will remain open until `bfd_close', and will not be affected
by BFD operations on other files.

   Possible errors are `bfd_error_no_memory',
`bfd_error_invalid_target' and `bfd_error_system_call'.
`bfd_openstreamr'
.................

*Synopsis*
     bfd *bfd_openstreamr();
   *Description*
Open a BFD for read access on an existing stdio stream.  When the BFD
is passed to `bfd_close', the stream will be closed.
`bfd_openw'
...........

*Synopsis*
     bfd *bfd_openw(CONST char *filename, CONST char *target);
   *Description*
Create a BFD, associated with file FILENAME, using the file format
TARGET, and return a pointer to it.

   Possible errors are `bfd_error_system_call', `bfd_error_no_memory',
`bfd_error_invalid_target'.
`bfd_close'
...........

*Synopsis*
     boolean bfd_close(bfd *abfd);
   *Description*
Close a BFD. If the BFD was open for writing, then pending operations
are completed and the file written out and closed. If the created file
is executable, then `chmod' is called to mark it as such.

   All memory attached to the BFD's obstacks is released.

   The file descriptor associated with the BFD is closed (even if it
was passed in to BFD by `bfd_fdopenr').
*Returns*
`true' is returned if all is ok, otherwise `false'.
`bfd_close_all_done'
....................

*Synopsis*
     boolean bfd_close_all_done(bfd *);
   *Description*
Close a BFD.  Differs from `bfd_close' since it does not complete any
pending operations.  This routine would be used if the application had
just used BFD for swapping and didn't want to use any of the writing
code.

   If the created file is executable, then `chmod' is called to mark it
as such.

   All memory attached to the BFD's obstacks is released.
*Returns*
`true' is returned if all is ok, otherwise `false'.
*Synopsis*
     bfd_size_type bfd_alloc_size(bfd *abfd);
   *Description*
Return the number of bytes in the obstacks connected to ABFD.
`bfd_create'
............

*Synopsis*
     bfd *bfd_create(CONST char *filename, bfd *templ);
   *Description*
Create a new BFD in the manner of `bfd_openw', but without opening a
file. The new BFD takes the target from the target used by TEMPLATE. The
format is always set to `bfd_object'.
`bfd_alloc_by_size_t'
.....................

*Synopsis*
     PTR bfd_alloc_by_size_t(bfd *abfd, size_t wanted);
   *Description*
Allocate a block of WANTED bytes of memory in the obstack attatched to
`abfd' and return a pointer to it.
