ELF_FLAG(3E)							  ELF_FLAG(3E)

NAME    [Toc]    [Back]

     elf_flagdata, elf_flagehdr, elf_flagelf, elf_flagphdr, elf_flagscn,
     elf_flagshdr - manipulate flags

SYNOPSIS    [Toc]    [Back]

     cc	[flag ...] file	...  -lelf [library ...]

     #include <libelf.h>

     unsigned elf_flagdata(Elf_Data *data, Elf_Cmd cmd,	unsigned flags);
     unsigned elf_flagehdr(Elf *elf, Elf_Cmd cmd, unsigned flags);

     unsigned elf_flagelf(Elf *elf, Elf_Cmd cmd, unsigned flags);
     unsigned elf_flagphdr(Elf *elf, Elf_Cmd cmd, unsigned flags);

     unsigned elf_flagscn(Elf_Scn *scn,	Elf_Cmd	cmd, unsigned flags);
     unsigned elf_flagshdr(Elf_Scn *scn, Elf_Cmd cmd, unsigned flags);

DESCRIPTION    [Toc]    [Back]

     These functions manipulate	the flags associated with various structures
     of	an ELF file.  Given an ELF descriptor (elf), a data descriptor (data),
     or	a section descriptor (scn), the	functions may set or clear the
     associated	status bits, returning the updated bits.  A null descriptor is
     allowed, to simplify error	handling; all functions	return zero for	this
     degenerate	case.

     cmd may have the following	values.

     ELF_C_CLR	       The functions clear the bits that are asserted in
		       flags.  Only the	non-zero bits in flags are cleared;
		       zero bits do not	change the status of the descriptor.

     ELF_C_SET	       The functions set the bits that are asserted in flags.
		       Only the	non-zero bits in flags are set;	zero bits do
		       not change the status of	the descriptor.

     Descriptions of the defined flags bits appear below.

     ELF_F_DIRTY       When the	program	intends	to write an ELF	file, this
		       flag asserts the	associated information needs to	be
		       written to the file.  Thus, for example,	a program that
		       wished to update	the ELF	header of an existing file
		       would call elf_flagehdr with this bit set in flags and
		       cmd equal to ELF_C_SET.	A later	call to	elf_update
		       would write the marked header to	the file.

     ELF_F_LAYOUT      Normally, the library decides how to arrange an output
		       file.  That is, it automatically	decides	where to place
		       sections, how to	align them in the file,	etc.  If this
		       bit is set for an ELF descriptor, the program assumes
		       responsibility for determining all file positions.
		       This bit	is meaningful only for elf_flagelf and applies



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ELF_FLAG(3E)							  ELF_FLAG(3E)



		       to the entire file associated with the descriptor.

     When a flag bit is	set for	an item, it affects all	the subitems as	well.
     Thus, for example,	if the program sets the	ELF_F_DIRTY bit	with
     elf_flagelf, the entire logical file is ``dirty.''

EXAMPLE    [Toc]    [Back]

     The following fragment shows how one might	mark the ELF header to be
     written to	the output file.

	  ehdr = elf32_getehdr(elf);
	  /* dirty ehdr	... */
	  elf_flagehdr(elf, ELF_C_SET, ELF_F_DIRTY);

SEE ALSO    [Toc]    [Back]

     elf(3E), elf_end(3E), elf_getdata(3E), elf_getehdr(3E), elf_update(3E).


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