sane-project-backends/include/sane/sanei_thread.h

/* sane - Scanner Access Now Easy.
   Copyright (C) 1998-2001 Yuri Dario
   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.
*/

/** @file sanei_thread.h
 * Header file to make porting fork, wait, and waitpid easier.
 *
 * This file contains helper functions for the OS/2 port (using threads
 * instead of forked processes). <b>Do not use these functions in the backends
 * directly</b>, they are used automatically by macros. Just include this file
 * in an \#ifdef HAVE_OS2_H statement if you use fork. If your reader process
 * has more than one argument, you also need to implement a
 * os2_reader_process() in your backend. The implementation should call your
 * own reader process. See mustek.c for an example.
 *    
 * The preprocessor is used for routing process-related function to OS/2
 * threaded code: in this way, Unix backends requires only minimal code
 * changes.
 *
 * @sa sanei.h sanei_backend.h
 */

  
#ifndef sanei_thread_h
#define sanei_thread_h
#include "../include/sane/config.h"

/** @name Internal functions 
 * @{
 */
/** <b>Do not use in backends</b>
 *
 * Wrapper for @c fork. 
 */
extern int sanei_thread_begin( void (*start)(void *arg), void* arg_list);

/** <b>Do not use in backends</b>
 *
 * Wrapper for @c kill. 
 */
extern int sanei_thread_kill( int pid, int sig);

/** <b>Do not use in backends</b>
 *
 * Wrapper for @c waitpid. 
 */
extern int sanei_thread_waitpid( int pid, int *stat_loc, int options);

/** <b>Do not use in backends</b>
 *
 * Wrapper for @c wait. 
 */
extern int sanei_thread_wait( int *stat_loc);
/* @} */

/** Reader process function.
 *
 * This wrapper is necessary if a backend's reader process need more than one
 * argument. Add a function to you backend with this name and let it call your
 * own reader process. See mustek.c for an example.
 */
static void os2_reader_process( void* data);

#ifdef HAVE_OS2_H
#define fork() 			sanei_thread_begin( os2_reader_process)
#define kill( a, b)		sanei_thread_kill( a,b)
#define waitpid( a, b, c)	sanei_thread_waitpid( a, b, c)
#endif

#endif /* sanei_thread_h */