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88 lines
2.0 KiB
C
88 lines
2.0 KiB
C
/* Creating a Pipe
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Copyright (C) 1991-2020 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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/* Read characters from the pipe and echo them to @code{stdout}. */
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void
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read_from_pipe (int file)
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{
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FILE *stream;
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int c;
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stream = fdopen (file, "r");
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while ((c = fgetc (stream)) != EOF)
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putchar (c);
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fclose (stream);
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}
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/* Write some random text to the pipe. */
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void
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write_to_pipe (int file)
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{
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FILE *stream;
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stream = fdopen (file, "w");
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fprintf (stream, "hello, world!\n");
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fprintf (stream, "goodbye, world!\n");
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fclose (stream);
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}
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int
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main (void)
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{
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pid_t pid;
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int mypipe[2];
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/*@group*/
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/* Create the pipe. */
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if (pipe (mypipe))
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{
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fprintf (stderr, "Pipe failed.\n");
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return EXIT_FAILURE;
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}
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/*@end group*/
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/* Create the child process. */
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pid = fork ();
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if (pid == (pid_t) 0)
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{
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/* This is the child process.
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Close other end first. */
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close (mypipe[1]);
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read_from_pipe (mypipe[0]);
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return EXIT_SUCCESS;
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}
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else if (pid < (pid_t) 0)
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{
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/* The fork failed. */
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fprintf (stderr, "Fork failed.\n");
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return EXIT_FAILURE;
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}
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else
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{
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/* This is the parent process.
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Close other end first. */
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close (mypipe[0]);
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write_to_pipe (mypipe[1]);
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return EXIT_SUCCESS;
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}
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}
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