mirror of https://gitee.com/openkylin/glib2.0.git
340 lines
10 KiB
C
340 lines
10 KiB
C
/* glib-unix.h - Unix specific integration
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* Copyright (C) 2011 Red Hat, Inc.
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* Copyright 2023 Collabora Ltd.
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*
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* SPDX-License-Identifier: LGPL-2.1-or-later
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __G_UNIX_H__
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#define __G_UNIX_H__
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/* We need to include the UNIX headers needed to use the APIs below,
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* but we also take this opportunity to include a wide selection of
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* other UNIX headers. If one of the headers below is broken on some
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* system, work around it here (or better, fix the system or tell
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* people to use a better one).
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*/
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#include <unistd.h>
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#include <errno.h>
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#include <sys/wait.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <glib.h>
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#include <glib/gstdio.h>
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#ifndef G_OS_UNIX
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#error "This header may only be used on UNIX"
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#endif
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G_BEGIN_DECLS
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/**
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* G_UNIX_ERROR:
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*
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* Error domain for API in the g_unix_ namespace. Note that there is no
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* exported enumeration mapping %errno. Instead, all functions ensure that
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* %errno is relevant. The code for all %G_UNIX_ERROR is always 0, and the
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* error message is always generated via g_strerror().
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*
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* It is expected that most code will not look at %errno from these APIs.
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* Important cases where one would want to differentiate between errors are
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* already covered by existing cross-platform GLib API, such as e.g. #GFile
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* wrapping `ENOENT`. However, it is provided for completeness, at least.
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*/
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#define G_UNIX_ERROR (g_unix_error_quark())
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GLIB_AVAILABLE_IN_2_30
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GQuark g_unix_error_quark (void);
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GLIB_AVAILABLE_IN_2_30
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gboolean g_unix_open_pipe (gint *fds,
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gint flags,
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GError **error);
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GLIB_AVAILABLE_IN_2_30
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gboolean g_unix_set_fd_nonblocking (gint fd,
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gboolean nonblock,
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GError **error);
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GLIB_AVAILABLE_IN_2_30
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GSource *g_unix_signal_source_new (gint signum);
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GLIB_AVAILABLE_IN_2_30
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guint g_unix_signal_add_full (gint priority,
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gint signum,
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GSourceFunc handler,
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gpointer user_data,
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GDestroyNotify notify);
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GLIB_AVAILABLE_IN_2_30
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guint g_unix_signal_add (gint signum,
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GSourceFunc handler,
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gpointer user_data);
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/**
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* GUnixFDSourceFunc:
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* @fd: the fd that triggered the event
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* @condition: the IO conditions reported on @fd
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* @user_data: user data passed to g_unix_fd_add()
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*
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* The type of functions to be called when a UNIX fd watch source
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* triggers.
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*
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* Returns: %FALSE if the source should be removed
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**/
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typedef gboolean (*GUnixFDSourceFunc) (gint fd,
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GIOCondition condition,
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gpointer user_data);
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GLIB_AVAILABLE_IN_2_36
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GSource *g_unix_fd_source_new (gint fd,
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GIOCondition condition);
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GLIB_AVAILABLE_IN_2_36
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guint g_unix_fd_add_full (gint priority,
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gint fd,
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GIOCondition condition,
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GUnixFDSourceFunc function,
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gpointer user_data,
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GDestroyNotify notify);
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GLIB_AVAILABLE_IN_2_36
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guint g_unix_fd_add (gint fd,
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GIOCondition condition,
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GUnixFDSourceFunc function,
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gpointer user_data);
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GLIB_AVAILABLE_IN_2_64
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struct passwd *g_unix_get_passwd_entry (const gchar *user_name,
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GError **error);
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/**
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* GUnixPipe:
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* @fds: A pair of file descriptors, each negative if closed or not yet opened.
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* The file descriptor with index %G_UNIX_PIPE_END_READ is readable.
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* The file descriptor with index %G_UNIX_PIPE_END_WRITE is writable.
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*
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* A Unix pipe. The advantage of this type over `int[2]` is that it can
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* be closed automatically when it goes out of scope, using `g_auto(GUnixPipe)`,
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* on compilers that support that feature.
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_TYPE_IN_2_80
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typedef struct {
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int fds[2];
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} GUnixPipe;
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/**
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* GUnixPipeEnd:
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* @G_UNIX_PIPE_END_READ: The readable file descriptor 0
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* @G_UNIX_PIPE_END_WRITE: The writable file descriptor 1
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*
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* Mnemonic constants for the ends of a Unix pipe.
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_TYPE_IN_2_80
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typedef enum
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{
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G_UNIX_PIPE_END_READ = 0,
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G_UNIX_PIPE_END_WRITE = 1
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} GUnixPipeEnd;
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/**
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* G_UNIX_PIPE_INIT:
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*
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* Initializer for a #GUnixPipe that has not yet been opened.
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* Both of its file descriptors are initialized to `-1` (invalid),
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* the same as if they had been closed.
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*
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* Since: 2.80
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*/
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#define G_UNIX_PIPE_INIT { { -1, -1 } } GLIB_AVAILABLE_MACRO_IN_2_80
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/* Suppress "Not available before" warnings when declaring the
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* implementations */
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G_GNUC_BEGIN_IGNORE_DEPRECATIONS
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/**
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* g_unix_pipe_open:
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* @self: A pair of file descriptors
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* @flags: Flags to pass to g_unix_open_pipe(), typically `O_CLOEXEC`
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* @error: Used to report an error on failure
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*
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* Open a pipe. This is the same as g_unix_open_pipe(), but uses the
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* #GUnixPipe data structure.
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*
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* Returns: %TRUE on success
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
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static inline gboolean
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g_unix_pipe_open (GUnixPipe *self,
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int flags,
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GError **error)
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{
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return g_unix_open_pipe (self->fds, flags, error);
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}
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/**
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* g_unix_pipe_get:
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* @self: A pair of file descriptors
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* @end: One of the ends of the pipe
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*
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* Return one of the ends of the pipe. It remains owned by @self.
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*
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* This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
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* [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
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* signal handler or a #GSpawnChildSetupFunc.
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*
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* This function preserves the value of `errno`.
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*
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* Returns: a non-negative file descriptor owned by @self, which must not
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* be closed by the caller, or a negative number if the corresponding
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* end of the pipe was already closed or stolen
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
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static inline int
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g_unix_pipe_get (GUnixPipe *self,
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GUnixPipeEnd end)
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{
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return self->fds[end];
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}
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/**
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* g_unix_pipe_steal:
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* @self: A pair of file descriptors
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* @end: One of the ends of the pipe
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*
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* Return one of the ends of the pipe. It becomes owned by the caller,
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* and the file descriptor in the data structure is set to `-1`,
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* similar to g_steal_fd().
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*
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* This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
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* [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
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* signal handler or a #GSpawnChildSetupFunc.
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*
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* This function preserves the value of `errno`.
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*
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* Returns: a non-negative file descriptor, which becomes owned by the
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* caller and must be closed by the caller if required, or a negative
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* number if the corresponding end of the pipe was already closed or stolen
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
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static inline int
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g_unix_pipe_steal (GUnixPipe *self,
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GUnixPipeEnd end)
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{
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return g_steal_fd (&self->fds[end]);
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}
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/**
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* g_unix_pipe_close:
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* @self: A pair of file descriptors
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* @end: One of the ends of the pipe
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* @error: Optionally used to report an error on failure
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*
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* Close one of the ends of the pipe and set the relevant member of @fds
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* to `-1` before returning, equivalent to g_clear_fd().
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*
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* Like g_close(), if closing the file descriptor fails, the error is
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* stored in both %errno and @error. If this function succeeds,
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* %errno is undefined.
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*
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* This function is async-signal safe if @error is %NULL and the relevant
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* member of @fds is either negative or a valid open file descriptor.
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* This makes it safe to call from a signal handler or a #GSpawnChildSetupFunc
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* under those conditions.
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* See [`signal(7)`](man:signal(7)) and
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* [`signal-safety(7)`](man:signal-safety(7)) for more details.
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*
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* To close both file descriptors and ignore any errors, use
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* g_unix_pipe_clear() instead.
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*
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* Returns: %TRUE on success
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
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static inline gboolean
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g_unix_pipe_close (GUnixPipe *self,
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GUnixPipeEnd end,
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GError **error)
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{
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return g_clear_fd (&self->fds[end], error);
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}
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/**
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* g_unix_pipe_clear:
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* @self: a #GUnixPipe
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*
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* Close both ends of the pipe, unless they have already been closed or
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* stolen. Any errors are ignored: use g_unix_pipe_close() or g_clear_fd()
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* if error-handling is required.
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*
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* This function is async-signal safe if @error is %NULL and each member
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* of @fds are either negative or a valid open file descriptor.
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* As a result, it is safe to call this function or use `g_auto(GUnixPipe)`
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* (on compilers that support it) in a signal handler or a
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* #GSpawnChildSetupFunc, as long as those conditions are ensured to be true.
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* See [`signal(7)`](man:signal(7)) and
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* [`signal-safety(7)`](man:signal-safety(7)) for more details.
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*
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* This function preserves the value of `errno`.
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*
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* Since: 2.80
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*/
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GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
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static inline void
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g_unix_pipe_clear (GUnixPipe *self)
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{
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/* Don't overwrite thread-local errno if closing the fd fails */
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int errsv = errno;
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if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_READ, NULL))
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{
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/* ignore */
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}
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if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_WRITE, NULL))
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{
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/* ignore */
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}
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errno = errsv;
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}
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G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC (GUnixPipe, g_unix_pipe_clear)
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GLIB_AVAILABLE_IN_2_80
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int g_closefrom (int lowfd);
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GLIB_AVAILABLE_IN_2_80
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int g_fdwalk_set_cloexec (int lowfd);
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G_GNUC_END_IGNORE_DEPRECATIONS
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G_END_DECLS
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#endif /* __G_UNIX_H__ */
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