.\"	$NetBSD: gelf_getphdr.3,v 1.3 2016/02/20 02:43:42 christos Exp $
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.\" Id: gelf_getphdr.3 189 2008-07-20 10:38:08Z jkoshy 
.\"
.Dd October 21, 2007
.Os
.Dt GELF_GETPHDR 3
.Sh NAME
.Nm elf32_getphdr ,
.Nm elf64_getphdr ,
.Nm gelf_getphdr
.Nd retrieve an ELF program header table
.Sh LIBRARY
.Lb libelf
.Sh SYNOPSIS
.In libelf.h
.Ft "Elf32_Phdr *"
.Fn elf32_getphdr "Elf *elf"
.Ft "Elf64_Phdr *"
.Fn elf64_getphdr "Elf *elf"
.In gelf.h
.Ft "GElf_Phdr *"
.Fn gelf_getphdr "Elf *elf" "int index" "GElf_Phdr *dst"
.Sh DESCRIPTION
These functions retrieve and translate ELF program header information
from an ELF descriptor, if this information exists.
.Pp
Functions
.Fn elf32_getphdr
and
.Fn elf64_getphdr
return a pointer to an array of translated
.Vt Elf32_Phdr
and
.Vt Elf64_Phdr
descriptors respectively.
These descriptors are described in
.Xr elf 5 .
The number of entries in this array may be determined using the
.Xr elf_getphnum 3
function.
.Pp
Function
.Fn gelf_getphdr
will retrieve the program header table entry at index
.Ar index
from ELF descriptor
.Ar elf.
The translated program header table entry will be written to the
address pointed to be argument
.Ar dst .
.Pp
Applications may inform the library of modifications to a program header table entry
by using the
.Xr elf_flagphdr 3
API.
Applications using the
.Xr gelf 3
interface need to use the
.Xr gelf_update_phdr 3
API to copy modifications to a program header entry back to the underlying
ELF descriptor.
.Sh RETURN VALUES
The functions a valid pointer if successful, or NULL in case an error
was encountered.
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width "[ELF_E_RESOURCE]"
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar elf
was NULL.
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar elf
was not a descriptor for an ELF object.
.It Bq Er ELF_E_ARGUMENT
Argument
.Ar dst
was NULL.
.It Bq Er ELF_E_ARGUMENT
Index
.Ar index
was out of range.
.It Bq Er ELF_E_CLASS
The class of ELF descriptor
.Ar elf
did not match the expected class of the function being called.
.It Bq Er ELF_E_HEADER
ELF descriptor
.Ar elf
did not possess an executable header.
.It Bq Er ELF_E_HEADER
ELF descriptor
.Ar elf
had a corrupt executable header.
.It Bq Er ELF_E_RESOURCE
An out of memory condition was detected.
.It Bq Er ELF_E_SECTION
The ELF descriptor in argument
.Ar elf
did not adhere to the conventions used for extended numbering.
.It Bq Er ELF_VERSION
ELF descriptor
.Ar elf
was of an unsupported version.
.El
.Sh SEE ALSO
.Xr elf 3 ,
.Xr elf32_getehdr 3 ,
.Xr elf32_newphdr 3 ,
.Xr elf64_getehdr 3 ,
.Xr elf64_newphdr 3 ,
.Xr elf_flagphdr 3 ,
.Xr elf_getphnum 3 ,
.Xr gelf 3 ,
.Xr gelf_getehdr 3 ,
.Xr gelf_newphdr 3 ,
.Xr gelf_update_phdr 3 ,
.Xr elf 5