1 files changed, 164 insertions, 0 deletions
diff --git a/include/sane/sanei_thread.h b/include/sane/sanei_thread.h
new file mode 100644
index 0000000..f152c93
--- /dev/null
+++ b/include/sane/sanei_thread.h
@@ -0,0 +1,164 @@
+/* sane - Scanner Access Now Easy.
+   Copyright (C) 1998-2001 Yuri Dario
+   Copyright (C) 2002-2003 Henning Meier-Geinitz (documentation)
+   Copyright (C) 2003-2004 Gerhard Jaeger (pthread/process support)
+   This file is part of the SANE package.
+
+   SANE 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 2 of the License, or (at your
+   option) any later version.
+
+   SANE 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 sane; see the file COPYING.  If not, write to the Free
+   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+   As a special exception, the authors of SANE give permission for
+   additional uses of the libraries contained in this release of SANE.
+
+   The exception is that, if you link a SANE library with other files
+   to produce an executable, this does not by itself cause the
+   resulting executable to be covered by the GNU General Public
+   License.  Your use of that executable is in no way restricted on
+   account of linking the SANE library code into it.
+
+   This exception does not, however, invalidate any other reasons why
+   the executable file might be covered by the GNU General Public
+   License.
+
+   If you submit changes to SANE to the maintainers to be included in
+   a subsequent release, you agree by submitting the changes that
+   those changes may be distributed with this exception intact.
+
+   If you write modifications of your own for SANE, it is your choice
+   whether to permit this exception to apply to your modifications.
+   If you do not wish that, delete this exception notice.
+
+*/
+
+/** @file sanei_thread.h
+ * Support for forking processes and threading.
+ *
+ * Backends should not use fork() directly because fork() does not work
+ * correctly on some platforms. Use the functions provided by sanei_thread
+ * instead. The build system decides if fork() or threads are used.
+ *
+ * Please keep in mind that the behaviour of the child process depends
+ * on if it's a process or thread especially concerning variables.
+ *
+ * In this file we use "task" as an umbrella term for process and thread.
+ *
+ * @sa sanei.h sanei_backend.h
+ */
+
+#ifndef sanei_thread_h
+#define sanei_thread_h
+#include "../include/sane/config.h"
+
+#ifdef USE_PTHREAD
+typedef pthread_t SANE_Pid;
+#else
+typedef int SANE_Pid;
+#endif
+
+/** Initialize sanei_thread.
+ *
+ * This function must be called before any other sanei_thread function.
+ */
+extern void sanei_thread_init (void);
+
+/** Do we use processes or threads?
+ *
+ * This function can be used to check if processes or threads are used.
+ *
+ * @return
+ * - SANE_TRUE - if processes are used (fork)
+ * - SANE_FALSE - i threads are used
+ */
+extern SANE_Bool sanei_thread_is_forked (void);
+
+/** Is SANE_Pid valid pid?
+ *
+ * This function can be used to check if thread/fork creation worked
+ * regardless of SANE_Pid's data type.
+ *
+ * @return
+ * - SANE_TRUE - if pid is not a valid process
+ * - SANE_FALSE - if pid is a valid process
+ */
+extern SANE_Bool sanei_thread_is_invalid (SANE_Pid pid);
+
+/** Spawn a new task.
+ *
+ * This function should be used to start a new task.
+ *
+ * @param func() function to call as child task
+ * @param args argument of the function (only one!)
+ *
+ * @return
+ * - task id
+ * - -1 if creating the new task failed
+ */
+extern SANE_Pid sanei_thread_begin (int (*func) (void *args), void *args);
+
+/** Terminate spawned task.
+ *
+ * This function terminates the task that was created with sanei_thread_begin.
+ *
+ * For processes, SIGTERM is sent. If threads are used, pthread_cancel()
+ * terminates the task.
+ *
+ * @param pid - the id of the task
+ *
+ * @return
+ * - 0 on success
+ * - any other value if an error occured while terminating the task
+ */
+extern int sanei_thread_kill (SANE_Pid pid);
+
+/** Send a signal to a task.
+ *
+ * This function can be used to send a signal to a task.
+ *
+ * For terminating the task, sanei_thread_kill() should be used.
+ *
+ * @param pid - the id of the task
+ * @param sig - the signal to send
+ *
+ * @return 
+ * - 0 - on success
+ * - any other value - if an error occured while sending the signal
+ */
+extern int sanei_thread_sendsig (SANE_Pid pid, int sig);
+
+/** Wait for task termination.
+ *
+ * This function waits until a task that has been terminated by 
+ * sanei_thread_kill(), sanei_thread_sendsys() or by any other means
+ * is finished.
+ *
+ * @param pid - the id of the task
+ * @param status - status of the task that has just finished
+ *
+ * @return
+ * - the pid of the task we have been waiting for
+ */
+extern SANE_Pid sanei_thread_waitpid (SANE_Pid pid, int *status);
+
+/** Check the current status of the spawned task
+ *
+ * 
+ * @param pid - the id of the task
+ *
+ * @return
+ * - SANE_STATUS_GOOD - if the task finished without errors
+ * - any other value - if the task finished unexpectantly or hasn't finished yet
+ */
+extern SANE_Status sanei_thread_get_status (SANE_Pid pid);
+
+#endif /* sanei_thread_h */