elf_rand(3elf)

elf_rand -- random archive member access

Synopsis

   cc [flag . . . ] file . . . -lelf [library] . . .
   
   #include <libelf.h>
   

   size_t elf_rand(Elf elf, size_t offset);

Description

elf_rand, elf_next, and elf_begin 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 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(3elf) 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.

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;
   }

References

ar(4), Intro(3elf), elf_begin(3elf), elf_getarsym(3elf), elf_next(3elf)