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.\" $Id: gelf_getchdr.3 3639 2020-10-20 16:07:02Z tig $
.\"
.Dd October 23, 2020
.Dt GELF_GETCHDR 3
.Os
.Sh NAME
.Nm elf32_getchdr ,
.Nm elf64_getchdr ,
.Nm gelf_getchdr
.Nd retrieve the compression header of a section
.Sh LIBRARY
.Lb libelf
.Sh SYNOPSIS
.In libelf.h
.Ft "Elf32_Chdr *"
.Fn elf32_getchdr "Elf_Scn *s"
.Ft "Elf64_Chdr *"
.Fn elf64_getchdr "Elf_Scn *s"
.In gelf.h
.Ft "GElf_Chdr *"
.Fn gelf_getchdr "Elf_Scn *scn" "GElf_Chdr *chdr"
.Sh DESCRIPTION
These functions return a pointer to the ELF Compression Header data
structure associated with section descriptor
.Ar scn .
.Pp
Function
.Fn elf32_getchdr
retrieves a pointer to an
.Vt Elf32_Chdr
structure.
Section descriptor
.Ar scn
must be associated with an ELF descriptor of class
.Dv ELFCLASS32 .
.Pp
Function
.Fn elf64_getchdr
retrieves a pointer to an
.Vt Elf64_Chdr
structure.
Section descriptor
.Ar scn
must be associated with an ELF descriptor of class
.Dv ELFCLASS64 .
.Pp
Function
.Fn gelf_getchdr
copies the values in the compression header associated with argument
.Ar scn
to the structure pointed to be argument
.Ar dst .
The
.Vt GElf_Chdr
data structure is described in
.Xr gelf 3 .
.Sh RETURN VALUES
Functions
.Fn elf32_getchdr
and
.Fn elf64_getchdr
return a valid pointer to the appropriate compression header on success
or NULL if an error was encountered.
.Pp
Function
.Fn gelf_getchdr
returns argument
.Ar dst
if successful, or NULL if 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_INVALID_SECTION_FLAGS
Arguments
.Ar scn
has invalid flags.
.It Bq Er ELF_E_INVALID_SECTION_TYPE
Argument
.Ar scn
has invalid type.
.It Bq Er ELF_E_NOT_COMPRESSED
Argument
.Ar scn
is not compressed.
.El
.Sh SEE ALSO
.Xr elf 3 ,
.Xr elf_getscn 3 ,
.Xr gelf 3 ,