builtins/psize.c

   1 /* psize.c - Find pipe size. */
   2
   3 /* Copyright (C) 1987, 1991 Free Software Foundation, Inc.
   4
   5    This file is part of GNU Bash, the Bourne Again SHell.
   6
   7    Bash is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 1, or (at your option)
  10    any later version.
  11
  12    Bash is distributed in the hope that it will be useful, but WITHOUT
  13    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15    License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with Bash; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
  20
  21 /*  Write output in 128-byte chunks until we get a sigpipe or write gets an
  22     EPIPE.  Then report how many bytes we wrote.  We assume that this is the
  23     pipe size. */
  24
  25 #include <stdio.h>
  26 #include <sys/types.h>
  27 #include <signal.h>
  28 #include <errno.h>
  29
  30 #include "../command.h"
  31 #include "../general.h"
  32 extern int errno;
  33
  34 int nw;
  35
  36 sighandler
  37 sigpipe (sig)
  38      int sig;
  39 {
  40   fprintf (stderr, "%d\n", nw);
  41   exit (0);
  42 }
  43
  44 main (argc, argv)
  45      int argc;
  46      char **argv;
  47 {
  48   char buf[128];
  49   register int i;
  50
  51   for (i = 0; i < 128; i++)
  52     buf[i] = ' ';
  53
  54   signal (SIGPIPE, sigpipe);
  55
  56   nw = 0;
  57   for (;;)
  58     {
  59       int n;
  60       n = write (1, buf, 128);
  61       nw += n;
  62     }
  63 }