elf_flag(3E) DG/UX 5.4R3.00 elf_flag(3E)
NAME
elf_flagdata, elf_flagehdr, elf_flagelf, elf_flagphdr, elf_flagscn,
elf_flagshdr - manipulate flags
SYNOPSIS
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
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 to the
entire file associated with the descriptor.
When a flag bit is set for an item, it affects all the subitems as
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elf_flag(3E) DG/UX 5.4R3.00 elf_flag(3E)
well. Thus, for example, if the program sets the ELF_F_DIRTY bit
with elf_flagelf, the entire logical file is ``dirty.''
EXAMPLE
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
elf(3E), elf_end(3E), elf_getdata(3E), elf_getehdr(3E),
elf_update(3E).
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