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Diffstat (limited to 'libical/src/libical/filelock.h')
-rw-r--r-- | libical/src/libical/filelock.h | 57 |
1 files changed, 0 insertions, 57 deletions
diff --git a/libical/src/libical/filelock.h b/libical/src/libical/filelock.h deleted file mode 100644 index dbe0715cc6..0000000000 --- a/libical/src/libical/filelock.h +++ /dev/null @@ -1,57 +0,0 @@ -/* - I Stole this from: - http://www.cis.temple.edu/~ingargio/old/cis307s96/readings/rwlockexample.html - - CIS 307: An example using Read/Write File Locks - [fcntl.h], [fcntl.c], [fcntlmain.c] - -In Stevens "Advanced Programming in the Unix Environment" we see ways to use -the Unix service fcntl to lock portions of a file for reading and writing in -the manner stated in the Reader and Writer problem [any number of readers at -a time, but writers must operate alone]. Here we have three files that adapt -and use the code from Stevens: - -*fcntl.h: Specification of the locking functions. -*fcntl.c: Implementation of the locking functions. -*fcntlmain.c: Driver that does a simple test of the locking functions. - -WARNING: A file lock request which is blocked can be interrupted by a -signal. In this case the lock operation returns EINTR. Thus we may think we -got a lock when we really don't. A solution is to block signals when -locking. Another solution is to test the value returned by the lock -operation and relock if the value is EINTR. Another solution, which we adopt -here, is to do nothing about it. - -fcntl.h - -*/ - -/* fcntl.h -- Defines mutexes in terms of read/write locks on files. - * filerwlock, filerwlockCreate, filerwlockDelete, - * filerwreadlock, filerwlockUnlock - */ - -typedef struct { - int fd; - int n; -} filerwlock; - -/* Create N read/write locks and returns the id of this cluster of locks. */ -filerwlock * filerwlockCreate(char *filename, int n); - -/* Delete the cluster of read/write locks associated with fl. */ -int filerwlockDelete(filerwlock *fl); - -/* Given the read/write lock cluster fl, lock its ith element */ -int filerwreadlock(filerwlock *fl, int i); - -int filerwwritelock(filerwlock *fl, int i); - -/* Given the lock cluster fl, unlock its ith element */ -int filerwunlock(filerwlock *fl, int i); - -/* Given the lock cluster fl, it read locks all its elements */ -int filerwlongreadlock(filerwlock *fl); - -/* Given the lock cluster fl, it unlocks all its elements */ -int filerwlongunlock(filerwlock *fl); |