/* * File : rw.c * * Title : Demo Readers/Writer. * * Short : A solution to the multi-reader's, one writer problem. * * Long : * * Author : Andrae Muys * * Date : 18 September 1997 * * Revised : 4-7-04 Shamelessly stolen and adapted by Rusty Sears. * Found the code at this url: * http://www.cs.nmsu.edu/~jcook/Tools/pthreads/rw.c */ #include #include #include #include #ifndef __LIBDFA_RW_H #define __LIBDFA_RW_H typedef struct { pthread_mutex_t *mut; int writers; int readers; int waiting; pthread_cond_t *writeOK, *readOK; } rwl; rwl *initlock (void); void readlock (rwl *lock, int d); int tryreadlock(rwl *lock, int d); void writelock (rwl *lock, int d); int trywritelock(rwl *lock, int d); /** aborts if called when no thread holds this latch. */ void assertlocked(rwl *lock); void downgradelock(rwl * lock); void unlock(rwl * lock); /** @deprecated in favor of unlock() */ void readunlock (rwl *lock); /** @deprecated in favor of unlock() */ void writeunlock (rwl *lock); void deletelock (rwl *lock); /* typedef struct { rwl *lock; int id; long delay; } rwargs; rwargs *newRWargs (rwl *l, int i, long d); void *reader (void *args); void *writer (void *args); */ #endif /* rw.h */