1 /* Pipe to a Subprocess
2 Copyright (C) 1991-2022 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (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
18 #include <stdio.h>
19 #include <stdlib.h>
20
21 void
write_data(FILE * stream)22 write_data (FILE * stream)
23 {
24 int i;
25 for (i = 0; i < 100; i++)
26 fprintf (stream, "%d\n", i);
27 if (ferror (stream))
28 {
29 fprintf (stderr, "Output to stream failed.\n");
30 exit (EXIT_FAILURE);
31 }
32 }
33
34 /*@group*/
35 int
main(void)36 main (void)
37 {
38 FILE *output;
39
40 output = popen ("more", "w");
41 if (!output)
42 {
43 fprintf (stderr,
44 "incorrect parameters or too many files.\n");
45 return EXIT_FAILURE;
46 }
47 write_data (output);
48 if (pclose (output) != 0)
49 {
50 fprintf (stderr,
51 "Could not run more or other error.\n");
52 }
53 return EXIT_SUCCESS;
54 }
55 /*@end group*/
56