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.\" $Id: gelf_getphdr.3,v 1.1 2019/02/01 05:27:38 jsg Exp $
.\"
.Dd October 21, 2007
.Dt GELF_GETPHDR 3
.Os
.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