elf_rand(S-osr5)

elf_rand -- random archive member access

Syntax

cc [flag . . . ] file . . . -lelf [library] . . .


#include <libelf.h>

size_t elf_rand(Elf *elf, size_t offset);

Description

elf_rand(S-osr5), elf_next(S-osr5), and elf_begin(S-osr5) manipulate simple object files and archives. elf is an ELF descriptor previously returned from elf_begin( ).

elf_rand( ) provides random archive processing, preparing elf to access an arbitrary archive member. elf must be a descriptor for the archive itself, not for a member within the archive. offset gives the byte offset from the beginning of the archive to the archive header of the desired member. See elf_getarsym(S-osr5) for more information about archive member offsets.

When elf_rand( ) works, it returns offset. Otherwise it returns 0, because an error occurred, elf was null, or the file was not an archive (no archive member can have a zero offset).

A program may mix random and sequential archive processing.

Diagnostics

Error conditions are identified through the routine elf_error(S-osr5).

Examples

An archive starts with a ``magic string'' that has SARMAG bytes; the initial archive member follows immediately. An application could thus provide the following function to rewind an archive (the function returns -1 for errors and 0 otherwise).

   #include <ar.h>
   #include <libelf.h>
   
   int
   rewindelf(Elf *elf)
   {
   	if (elf_rand(elf, (size_t)SARMAG) == SARMAG)
   		return 0;
   	return -1;
   }

Standards conformance