gl/tests/test-fadvise.c

   1 /* Test that fadvise works as advertised.
   2    Copyright (C) 2010-2023 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Pádraig Brady.  */
  18
  19 #include <config.h>
  20 #include <stdio.h>
  21
  22 #include "fadvise.h"
  23
  24 /* We ignore any errors as these hints are only advisory.
  25  * There is the chance one can pass invalid ADVICE, which will
  26  * not be indicated, but given the simplicity of the interface
  27  * this is unlikely.  Also not returning errors allows the
  28  * unconditional passing of descriptors to non standard files,
  29  * which will just be ignored if unsupported.  */
  30
  31 int
  32 main (void)
  33 {
  34   /* Valid.  */
  35   fadvise (stdin, FADVISE_SEQUENTIAL);
  36   fdadvise (fileno (stdin), 0, 0, FADVISE_RANDOM);
  37
  38   /* Ignored.  */
  39   fadvise (nullptr, FADVISE_RANDOM);
  40
  41   /* Invalid.  */
  42   fdadvise (42, 0, 0, FADVISE_RANDOM);
  43   /* Unfortunately C enums are not types.
  44      One could hack type safety by wrapping in a struct,
  45      but it's probably not worth the complexity in this case.  */
  46   fadvise (stdin, FADVISE_SEQUENTIAL + FADVISE_RANDOM);
  47   fadvise (stdin, 4242);
  48
  49   return 0;
  50 }