grp/getgrgid.c

   1 /* Copyright (C) 1991 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23 #include <grp.h>
  24
  25 /* Search for an entry with a matching group ID.  */
  26 struct group *
  27 DEFUN(getgrgid, (gid), register gid_t gid)
  28 {
  29   static PTR info = NULL;
  30   register FILE *stream;
  31   register struct group *g;
  32
  33   if (info == NULL)
  34     {
  35       info = __grpalloc();
  36       if (info == NULL)
  37         return NULL;
  38     }
  39
  40   stream = __grpopen();
  41   if (stream == NULL)
  42     return NULL;
  43
  44   while ((g = __grpread(stream, info)) != NULL)
  45     if (g->gr_gid == (gid_t) gid)
  46       break;
  47
  48   (void) fclose(stream);
  49   return g;
  50 }