sysdeps/posix/getdtsz.c

   1 /* Copyright (C) 1991-2024 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <limits.h>
  19 #include <unistd.h>
  20 #include <sys/resource.h>
  21
  22 /* Return the maximum number of file descriptors
  23    the current process could possibly have.  */
  24 int
  25 __getdtablesize (void)
  26 {
  27   struct rlimit ru;
  28
  29   /* This should even work if `getrlimit' is not implemented.  POSIX.1
  30      does not define this function but we will generate a stub which
  31      returns -1.  */
  32   return __getrlimit (RLIMIT_NOFILE, &ru) < 0 ? OPEN_MAX : ru.rlim_cur;
  33 }
  34
  35 weak_alias (__getdtablesize, getdtablesize)