kopia lustrzana https://gitlab.com/sane-project/backends
98 wiersze
3.5 KiB
C
98 wiersze
3.5 KiB
C
/* sane - Scanner Access Now Easy.
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Copyright (C) 2005 Gerhard Jaeger <gerhard@gjaeger.de>
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This file is part of the SANE package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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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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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA.
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As a special exception, the authors of SANE give permission for
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additional uses of the libraries contained in this release of SANE.
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The exception is that, if you link a SANE library with other files
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to produce an executable, this does not by itself cause the
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resulting executable to be covered by the GNU General Public
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License. Your use of that executable is in no way restricted on
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account of linking the SANE library code into it.
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This exception does not, however, invalidate any other reasons why
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the executable file might be covered by the GNU General Public
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License.
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If you submit changes to SANE to the maintainers to be included in
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a subsequent release, you agree by submitting the changes that
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those changes may be distributed with this exception intact.
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If you write modifications of your own for SANE, it is your choice
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whether to permit this exception to apply to your modifications.
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If you do not wish that, delete this exception notice.
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*/
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/** @file sanei_access.h
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* Interface file for the sanei_access functions.
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*
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* The idea is to provide some simple locking/unlocking mecanism, which
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* can be used to protect device access from more than one frontend
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* simultaneously.
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*/
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#ifndef sanei_access_h
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#define sanei_access_h
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#include "../include/sane/config.h"
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#include "../include/sane/sane.h"
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/** Initialize sanei_access.
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*
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* This function must be called before any other sanei_access function.
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*
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* @param backend - backend name, who uses this lib
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*/
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extern void sanei_access_init( const char * backend );
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/** Set a lock.
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*
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* The function tries to open/create exclusively a lock file in
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* $PATH_SANE_LOCK_DIR.
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* If the file could be created successfully, the function fills in the
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* process ID.
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* The complete filename of the lockfile is created as follows:
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* $PATH_SANE_LOCK_DIR/LCK..<devicename>
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* If the lock could not be set, the function tries it until the timeout
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* period has been elapsed.
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*
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* @param devicename - unique part of the lockfile name
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* @param timeout - time in seconds to try to set a lock
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* @return
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* - SANE_STATUS_GOOD - if the lock has been successfully set
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* - SANE_STATUS_ACCESS_DENIED - the lock could not set
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*/
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extern SANE_Status sanei_access_lock( const char * devicename, SANE_Word timeout );
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/** Unlock a previously set lock.
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*
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* The function tries to unlock a previously created lock. The lockfile will be
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* closed and removed.
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*
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* @param devicename - part of the lockfile name, use for sanei_acess_lock()
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* @return
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* - SANE_STATUS_GOOD - currently the one and only return value
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*/
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extern SANE_Status sanei_access_unlock( const char * devicename );
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#endif /* sanei_access_h */
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