diff options
| -rw-r--r-- | man/man3/pthread_cond_init.3 | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/man/man3/pthread_cond_init.3 b/man/man3/pthread_cond_init.3 index 0045e7ecee..88600b3a5b 100644 --- a/man/man3/pthread_cond_init.3 +++ b/man/man3/pthread_cond_init.3 @@ -115,6 +115,7 @@ if all threads always acquire the mutex before signaling the condition, this guarantees that the condition cannot be signaled (and thus ignored) between the time a thread locks the mutex and the time it waits on the condition variable. +See CAVEATS below. .P .BR pthread_cond_timedwait () atomically unlocks @@ -240,6 +241,29 @@ Some threads are currently waiting on .BR gettimeofday (2), .BR nanosleep (2). . +.SH CAVEATS +The implementation of the provided functions until +glibc 2.25 used an internal data lock. +This lock did not support priority-inheritance and +was subject to unbounded priority inversion, +visible on a real-time system. +.P +After the rewrite of the implementation in glibc 2.25 +the usage of internal lock changed. +The internal lock is always acquired by +the signaling functions +.BR pthread_cond_signal () +and +.BR pthread_cond_broadcast (). +The waiting function acquires the lock +if the waiting process was interrupted. +The interruption can be caused for instance +by a specified timeout, +and denoted by the error value +.BR ETIMEDOUTA , +or by a received signal, +which is denoted by the error value +.BR EINTR . . .SH EXAMPLE Consider two shared variables |