ELF_GETSCN(3)

ELF_GETSCN(3) | Library Functions Manual | ELF_GETSCN(3)

# NAME

elf_getscn, elf_ndxscn, elf_newscn, elf_nextscn — get/allocate section information for an ELF object

# LIBRARY

ELF Access Library (libelf, -lelf)

# SYNOPSIS

#include <libelf.h>
Elf_Scn *
elf_getscn(Elf *elf, size_t index);
size_t
elf_ndxscn(Elf_Scn *scn);
Elf_Scn *
elf_newscn(Elf *elf);
Elf_Scn *
elf_nextscn(Elf *elf, Elf_Scn *scn);

# DESCRIPTION

These functions are used to iterate through the sections associated with an ELF descriptor.
Function elf_getscn() will return a section descriptor for the section at index index in the object denoted by ELF descriptor elf. An error will be signalled if the specified section does not exist.
Function elf_ndxscn() returns the section table index associated with section descriptor scn.
Function elf_newscn() creates a new section and appends it to the list of sections associated with descriptor elf. The library will automatically increment the e_shnum field of the ELF header associated with descriptor elf, and will set the `ELF_F_DIRTY` flag on the returned section descriptor. For ELF descriptors opened for writing, the ELF library will automatically create an empty section at index zero (`SHN_UNDEF`) on the first call to elf_newscn().
Function elf_nextscn() takes a section descriptor scn and returns a pointer to the section descriptor at the next higher index. Argument scn is allowed to be NULL, in which case this function will return a pointer to the section descriptor at index 1. If no further sections are present, function elf_nextscn() will return a NULL pointer.

# RETURN VALUES

Functions elf_getscn(), elf_newscn() and elf_nextscn() return a valid pointer to a section descriptor if successful, or NULL if an error occurs.
Function elf_ndxscn() returns a valid section table index if successful, or `SHN_UNDEF` if an error occurs.

# ERRORS

These functions may fail with the following errors:

[`ELF_E_ARGUMENT`]
  Arguments elf or scn were NULL.
[`ELF_E_ARGUMENT`]
  Argument index exceeded the current number of sections in the ELF object.
[`ELF_E_ARGUMENT`]
  Argument elf was not a descriptor for an ELF file.
[`ELF_E_ARGUMENT`]
  Section descriptor scn was not associated with ELF descriptor elf.
[`ELF_E_CLASS`]
  Descriptor elf was of an unknown ELF class.
[`ELF_E_SECTION`]
  Argument elf specified extended section numbering in the ELF header with the section header at index `SHN_UNDEF` not being of type `SHT_NULL`.

# SEE ALSO

elf(3), elf_flagdata(3), elf_flagscn(3), elf_getdata(3), elf_getshdr(3), gelf(3)

October 22, 2007 | NetBSD 8.3