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- /* LIBGIMP - The GIMP Library
- * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- *
- * $Revision: 1.7 $
- */
-
- #include <glib.h>
-
- #include "gimpsignal.h"
-
-
- /* Courtesy of Austin Donnelly 06-04-2000 to address bug #2742 */
-
- /**
- * gimp_signal_private:
- * @signum: Selects signal to be handled see man 5 signal (or man 7 signal)
- * @handler: Handler that maps to signum. Invoked by O/S.
- * Handler gets signal that caused invocation. Corresponds
- * to the @sa_handler field of the @sigaction struct.
- * @flags: Preferences. OR'ed SA_<xxx>. See man sigaction. Corresponds
- * to the @sa_flags field of the @sigaction struct.
- *
- * This function furnishes a workalike for signal(2) but
- * which internally invokes sigaction(2) after certain
- * sa_flags are set; these primarily to ensure restarting
- * of interrupted system calls. See sigaction(2) It is a
- * aid to transition and not new development: that effort
- * should employ sigaction directly. [gosgood 18.04.2000]
- *
- * Cause @handler to be run when @signum is delivered. We
- * use sigaction(2) rather than signal(2) so that we can control the
- * signal handler's environment completely via @flags: some signal(2)
- * implementations differ in their sematics, so we need to nail down
- * exactly what we want. [austin 06.04.2000]
- *
- * Returns: A reference to the signal handling function which was
- * active before the call to gimp_signal_private().
- */
- GimpSignalHandlerFunc
- gimp_signal_private (gint signum,
- GimpSignalHandlerFunc handler,
- gint flags)
- {
- gint ret;
- struct sigaction sa;
- struct sigaction osa;
-
- /* The sa_handler (mandated by POSIX.1) and sa_sigaction (a
- * common extension) are often implemented by the OS as members
- * of a union. This means you CAN NOT set both, you set one or
- * the other. Caveat programmer!
- */
-
- /* Passing gimp_signal_private a gimp_sighandler of NULL is not
- * an error, and generally results in the action for that signal
- * being set to SIG_DFL (default behavior). Many OSes define
- * SIG_DFL as (void (*)()0, so setting sa_handler to NULL is
- * the same thing as passing SIG_DFL to it.
- */
- sa.sa_handler = handler;
-
- /* Mask all signals while handler runs to avoid re-entrancy
- * problems.
- */
- sigfillset (&sa.sa_mask);
-
- sa.sa_flags = flags;
-
- ret = sigaction (signum, &sa, &osa);
-
- if (ret < 0)
- g_error ("unable to set handler for signal %d\n", signum);
-
- return (GimpSignalHandlerFunc) osa.sa_handler;
- }
-