elf_cntl(ELF)
elf_cntl --
control a file descriptor
Synopsis
cc [flag . . . ] file . . . -lelf [library] . . .
#include <libelf.h>
int elf_cntl(Elf elf, Elf_Cmd cmd);
Description
elf_cntl
instructs the library to modify its behavior with respect to an
ELF
descriptor,
elf.
As
elf_begin(ELF)
describes, an
ELF
descriptor can have multiple activations,
and multiple
ELF
descriptors may share a single file descriptor.
Generally,
elf_cntl
commands apply to all activations of
elf.
Moreover, if the
ELF
descriptor is associated
with an archive file, descriptors for members within
the archive will also be affected as described below.
Unless stated otherwise, operations on archive members
do not affect the descriptor for the containing archive.
The
cmd
argument tells what actions to take and may have the following values.
ELF_C_FDDONE-
This value tells the library not to use the file descriptor
associated with
elf.
A program should use this command when it has requested all the
information it cares to use and wishes to avoid the overhead
of reading the rest of the file.
The memory for all completed operations remains valid, but later
file operations, such as the initial
elf_getdata
for a section, will fail if the data is not in memory already.
ELF_C_FDREAD-
This command is similar to
ELF_C_FDDONE,
except it forces the library to read the rest of the file.
A program should use this command when it must close the file
descriptor but has not yet read everything it needs from the file.
After
elf_cntl
completes the
ELF_C_FDREAD
command, future operations, such as
elf_getdata,
will use the memory version of the file without needing
to use the file descriptor.
If
elf_cntl
succeeds, it returns zero.
Otherwise
elf
was null or an error occurred, and the function returns -1.
References
Intro(ELF),
elf_begin(ELF),
elf_getdata(ELF),
elf_rawfile(ELF)
Notices
If the program wishes to use the ``raw'' operations [see
elf_rawdata,
which
elf_getdata(ELF)
describes, and
elf_rawfile(ELF)]
after
disabling the file descriptor with
ELF_C_FDDONE or ELF_C_FDREAD,
it must execute the raw operations explicitly beforehand.
Otherwise, the raw file operations will fail.
Calling
elf_rawfile
makes the entire image available, thus supporting subsequent
elf_rawdata
calls.
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 - 02 June 2005