Linux IPC Sync (ii): Read/write lock

The allocation rules for read and write locks are as follows:

1. As long as no thread holds a specified read-write lock for writing, then any number of threads can hold the read-write lock for reading;

2. A read-write lock can be allocated for write only if no thread holds a specified read-write lock for reading or for writing.

This type of access is also known as shared-exclusive lockout (shared-exclusion)

So I think of a scenario like this:

Thread A to write data, the lock has not been blocked, the period of constant readers to read, thread a starved ... (Verified by the experiment)

int   Pthread_rwlock_init (pthread_rwlock_t *, pthread_rwlockattr_t *); int   Pthread_rwlock_rdlock (pthread_rwlock_t *); int   Pthread_rwlock_tryrdlock (pthread_rwlock_t *); int   Pthread_rwlock_wrlock (pthread_rwlock_t *); int   Pthread_rwlock_trywrlock (pthread_rwlock_t *); int   Pthread_rwlock_unlock (pthread_rwlock_t *); int   Pthread_rwlock_destroy (pthread_rwlock_t *);

Same:

Read-write locks can also be used between processes , by setting the property to Pthread_process_shared

#include <pthread.h>int  pthread_rwlockattr_getpshared (constint *valptr) ; int  int value)

Linux IPC Sync (ii): Read/write lock