stdio-common/tst-dprintf-length.c

   1 /* Test that dprintf returns the expected length.
   2    Copyright (C) 2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <support/check.h>
  22 #include <sys/socket.h>
  23 #include <unistd.h>
  24
  25 static int
  26 do_test (void)
  27 {
  28   /* Use a datagram socket to check that everything arrives in one packet.
  29      The dprintf function should perform a single write call.  */
  30   int fds[2];
  31   TEST_VERIFY_EXIT (socketpair (AF_LOCAL, SOCK_DGRAM, 0, fds) == 0);
  32
  33   TEST_COMPARE (dprintf (fds[0], "(%d)%s[%d]", 123, "---", 4567), 14);
  34
  35   char buf[32];
  36   ssize_t ret = read (fds[1], buf, sizeof (buf));
  37   TEST_VERIFY_EXIT (ret > 0);
  38   TEST_COMPARE_BLOB (buf, ret, "(123)---[4567]", strlen ("(123)---[4567]"));
  39
  40   close (fds[1]);
  41   close (fds[0]);
  42   return 0;
  43 }
  44
  45 #include <support/test-driver.c>