elf_cntl(3ELF) ELF Library Functions elf_cntl(3ELF)NAMEelf_cntl - control an elf file descriptor
SYNOPSIS
cc [ flag ... ] file ... -lelf [ library ... ]
#include <libelf.h>
int elf_cntl(Elf *elf, Elf_Cmd cmd);
DESCRIPTIONelf_cntl() instructs the library to modify its behavior with respect to
an ELF descriptor, elf. As elf_begin(3ELF) describes, an ELF descrip‐
tor 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, opera‐
tions on archive members do not affect the descriptor for the contain‐
ing 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 com‐
pleted operations remains valid, but later file opera‐
tions, such as the initial elf_getdata() for a section,
will fail if the data are 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 pro‐
gram 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 0. Otherwise elf was NULL or an
error occurred, and the function returns −1.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Stable │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOelf(3ELF), elf_begin(3ELF), elf_getdata(3ELF), elf_rawfile(3ELF),
libelf(3LIB), attributes(5)NOTES
If the program wishes to use the ``raw'' operations (see elf_rawdata(),
which elf_getdata(3ELF) describes, and elf_rawfile(3ELF)) after dis‐
abling 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.
SunOS 5.10 11 Jul 2001 elf_cntl(3ELF)
