elf_flag(3E)      MISC. REFERENCE MANUAL PAGES       elf_flag(3E)



NAME
     elfflagdata,   elfflagehdr,   elfflagelf,   elfflagphdr,
     elfflagscn, elfflagshdr - manipulate flags

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

     #include <libelf.h>

     unsigned elfflagdata(ElfData *data, ElfCmd cmd, unsigned flags);
     unsigned elfflagehdr(Elf *elf, ElfCmd cmd, unsigned flags);

     unsigned elfflagelf(Elf *elf, ElfCmd cmd, unsigned flags);
     unsigned elfflagphdr(Elf *elf, ElfCmd cmd, unsigned flags);

     unsigned elfflagscn(ElfScn *scn, ElfCmd cmd, unsigned flags);
     unsigned elfflagshdr(ElfScn *scn, ElfCmd 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.

     ELFCCLR         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.

     ELFCSET         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.  Descrip-
                       tions of the  defined  flags  bits  appear
                       below.

     ELFFDIRTY       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 elfflagehdr with
                       this bit set in flags  and  cmd  equal  to
                       ELFCSET.   A  later  call  to elfupdate
                       would write the marked header to the file.

     ELFFLAYOUT      Normally,  the  library  decides  how   to
                       arrange  an  output  file.   That  is,  it
                       automatically  decides  where   to   place



                    Last change: ELF Library                    1

elf_flag(3E)      MISC. REFERENCE MANUAL PAGES       elf_flag(3E)



                       sections,  how  to align them in the file,
                       etc.  If  this  bit  is  set  for  an  ELF
                       descriptor,  the program assumes responsi-
                       bility for determining all file positions.
                       This    bit   is   meaningful   only   for
                       elfflagelf 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 well.  Thus, for exam-
                       ple, if the program sets  the  ELFFDIRTY
                       bit  with  elfflagelf, 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 = elf32getehdr(elf);
          /* dirty ehdr ... */
          elfflagehdr(elf, ELFCSET, ELFFDIRTY);

SEE ALSO
     elf(3E), elfend(3E), elfgetdata(3E), elfgetehdr(3E),
     elfupdate(3E).
































                    Last change: ELF Library                    2