apr_{thread,proc,global}_timedlock() with negative timeout is now equivalent

to apr_{thread,proc,global}_trylock(), i.e. immediate attempt to acquire the
lock (but returning APR_TIMEUP if busy).



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1790632 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 3 insertions, 1 deletions

diff --git a/include/apr_thread_mutex.h b/include/apr_thread_mutex.h
index 5279a9fa6..8eb617291 100644
--- a/include/apr_thread_mutex.h
+++ b/include/apr_thread_mutex.h
@@ -87,7 +87,9 @@ APR_DECLARE(apr_status_t) apr_thread_mutex_trylock(apr_thread_mutex_t *mutex);
  * Attempt to acquire the lock for the given mutex until timeout expires.
  * If the acquisition time outs, the call returns with APR_TIMEUP.
  * @param mutex the mutex on which to attempt the lock acquiring.
- * @param timeout the relative timeout (microseconds)
+ * @param timeout the relative timeout (microseconds).
+ * @note A timeout negative or nul means immediate attempt, returning
+ *       APR_TIMEUP without blocking if it the lock is already acquired.
  */
 APR_DECLARE(apr_status_t) apr_thread_mutex_timedlock(apr_thread_mutex_t *mutex,
                                                  apr_interval_time_t timeout);