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authorJörg Frings-Fürst <debian@jff-webhosting.net>2014-10-06 14:00:40 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2014-10-06 14:00:40 +0200
commit6e9c41a892ed0e0da326e0278b3221ce3f5713b8 (patch)
tree2e301d871bbeeb44aa57ff9cc070fcf3be484487 /include/sane/sanei_access.h
Initial import of sane-backends version 1.0.24-1.2
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diff --git a/include/sane/sanei_access.h b/include/sane/sanei_access.h
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+/* sane - Scanner Access Now Easy.
+
+ Copyright (C) 2005 Gerhard Jaeger <gerhard@gjaeger.de>
+
+ This file is part of the SANE package.
+
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ MA 02111-1307, 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_access.h
+ * Interface file for the sanei_access functions.
+ *
+ * The idea is to provide some simple locking/unlocking mecanism, which
+ * can be used to protect device access from more than one frontend
+ * simultaneously.
+ */
+
+#ifndef sanei_access_h
+#define sanei_access_h
+
+#include "../include/sane/config.h"
+#include "../include/sane/sane.h"
+
+/** Initialize sanei_access.
+ *
+ * This function must be called before any other sanei_access function.
+ *
+ * @param backend - backend name, who uses this lib
+ */
+extern void sanei_access_init( const char * backend );
+
+/** Set a lock.
+ *
+ * The function tries to open/create exclusively a lock file in
+ * $PATH_SANE_LOCK_DIR.
+ * If the file could be created successfully, the function fills in the
+ * process ID.
+ * The complete filename of the lockfile is created as follows:
+ * $PATH_SANE_LOCK_DIR/LCK..&lt;devicename&gt;
+ * If the lock could not be set, the function tries it until the timeout
+ * period has been elapsed.
+ *
+ * @param devicename - unique part of the lockfile name
+ * @param timeout - time in seconds to try to set a lock
+ * @return
+ * - SANE_STATUS_GOOD - if the lock has been successfully set
+ * - SANE_STATUS_ACCESS_DENIED - the lock could not set
+ */
+extern SANE_Status sanei_access_lock( const char * devicename, SANE_Word timeout );
+
+/** Unlock a previously set lock.
+ *
+ * The function tries to unlock a previously created lock. The lockfile will be
+ * closed and removed.
+ *
+ * @param devicename - part of the lockfile name, use for sanei_acess_lock()
+ * @return
+ * - SANE_STATUS_GOOD - currently the one and only return value
+ */
+extern SANE_Status sanei_access_unlock( const char * devicename );
+
+#endif /* sanei_access_h */