-/* Creation of subprocesses, communicating via pipes.
- Copyright (C) 2001-2003, 2006, 2008-2010 Free Software Foundation, Inc.
- Written by Bruno Haible <haible@clisp.cons.org>, 2001.
-
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-#ifndef _PIPE_H
-#define _PIPE_H
-
-/* Get pid_t. */
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-
-#include <stdbool.h>
-
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-
-/* All these functions create a subprocess and don't wait for its termination.
- They return the process id of the subprocess. They also return in fd[]
- one or two file descriptors for communication with the subprocess.
- If the subprocess creation fails: if exit_on_error is true, the main
- process exits with an error message; otherwise, an error message is given
- if null_stderr is false, then -1 is returned, with errno set, and fd[]
- remain uninitialized.
-
- After finishing communication, the caller should call wait_subprocess()
- to get rid of the subprocess in the process table.
-
- If slave_process is true, the child process will be terminated when its
- creator receives a catchable fatal signal or exits normally. If
- slave_process is false, the child process will continue running in this
- case, until it is lucky enough to attempt to communicate with its creator
- and thus get a SIGPIPE signal.
-
- If exit_on_error is false, a child process id of -1 should be treated the
- same way as a subprocess which accepts no input, produces no output and
- terminates with exit code 127. Why? Some errors during posix_spawnp()
- cause the function posix_spawnp() to return an error code; some other
- errors cause the subprocess to exit with return code 127. It is
- implementation dependent which error is reported which way. The caller
- must treat both cases as equivalent.
-
- It is recommended that no signal is blocked or ignored (i.e. have a
- signal handler with value SIG_IGN) while any of these functions is called.
- The reason is that child processes inherit the mask of blocked signals
- from their parent (both through posix_spawn() and fork()/exec());
- likewise, signals ignored in the parent are also ignored in the child
- (except possibly for SIGCHLD). And POSIX:2001 says [in the description
- of exec()]:
- "it should be noted that many existing applications wrongly
- assume that they start with certain signals set to the default
- action and/or unblocked. In particular, applications written
- with a simpler signal model that does not include blocking of
- signals, such as the one in the ISO C standard, may not behave
- properly if invoked with some signals blocked. Therefore, it is
- best not to block or ignore signals across execs without explicit
- reason to do so, and especially not to block signals across execs
- of arbitrary (not closely co-operating) programs." */
-
-/* Open a pipe for output to a child process.
- * The child's stdout goes to a file.
- *
- * write system read
- * parent -> fd[0] -> STDIN_FILENO -> child
- *
- * Note: When writing to a child process, it is useful to ignore the SIGPIPE
- * signal and the EPIPE error code.
- */
-extern pid_t create_pipe_out (const char *progname,
- const char *prog_path, char **prog_argv,
- const char *prog_stdout, bool null_stderr,
- bool slave_process, bool exit_on_error,
- int fd[1]);
-
-/* Open a pipe for input from a child process.
- * The child's stdin comes from a file.
- *
- * read system write
- * parent <- fd[0] <- STDOUT_FILENO <- child
- *
- */
-extern pid_t create_pipe_in (const char *progname,
- const char *prog_path, char **prog_argv,
- const char *prog_stdin, bool null_stderr,
- bool slave_process, bool exit_on_error,
- int fd[1]);
-
-/* Open a bidirectional pipe.
- *
- * write system read
- * parent -> fd[1] -> STDIN_FILENO -> child
- * parent <- fd[0] <- STDOUT_FILENO <- child
- * read system write
- *
- * Note: When writing to a child process, it is useful to ignore the SIGPIPE
- * signal and the EPIPE error code.
- *
- * Note: The parent process must be careful to avoid deadlock.
- * 1) If you write more than PIPE_MAX bytes or, more generally, if you write
- * more bytes than the subprocess can handle at once, the subprocess
- * may write its data and wait on you to read it, but you are currently
- * busy writing.
- * 2) When you don't know ahead of time how many bytes the subprocess
- * will produce, the usual technique of calling read (fd, buf, BUFSIZ)
- * with a fixed BUFSIZ will, on Linux 2.2.17 and on BSD systems, cause
- * the read() call to block until *all* of the buffer has been filled.
- * But the subprocess cannot produce more data until you gave it more
- * input. But you are currently busy reading from it.
- */
-extern pid_t create_pipe_bidi (const char *progname,
- const char *prog_path, char **prog_argv,
- bool null_stderr,
- bool slave_process, bool exit_on_error,
- int fd[2]);
-
-/* The name of the "always silent" device. */
-#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
-/* Native Woe32 API. */
-# define DEV_NULL "NUL"
-#else
-/* Unix API. */
-# define DEV_NULL "/dev/null"
-#endif
-
-
-#ifdef __cplusplus
-}
-#endif
-
-
-#endif /* _PIPE_H */
+/* Obsolete; consider using spawn-pipe.h instead. */
+#include "spawn-pipe.h"
projects / gnulib.git / blobdiff