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.Dd October 16, 2016 .Dt CND 3 .Os .Sh NAME .Nm cnd .Nd condition variable functions .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS n threads.h .Ft int .Fn cnd_broadcast "cnd_t *cond" .Ft void .Fn cnd_destroy "cnd_t *cond" .Ft int .Fn cnd_init "cnd_t *cond" .Ft int .Fn cnd_signal "cnd_t *cond" .Ft int .Fo cnd_timedwait .Fa "cnd_t * __restrict cond" .Fa "mtx_t * __restrict mtx" .Fa "const struct timespec * __restrict ts" .Fc .Ft int .Fn cnd_wait "cnd_t *cond" "mtx_t *mtx" .Sh DESCRIPTION The .Fn cnd_broadcast function unblocks all threads that are blocked on a condition variable .Fa cond at the time of the call. If no thread is blocked on the .Fa cond condition variable at the time of the call, the function does nothing and returns success.
p The .Fn cnd_destroy function destroys the .Fa cond condition variable.
p The .Fn cnd_init function initializes a new .Fa cond variable.
p The .Fn cnd_signal function unblock one thread that currently waits on the .Fa cond variable. If there are no threads blocked, .Fn cnd_signal does nothing and returns success.
p The .Fn cnd_timedwait function atomically unlocks the mutex .Fa mtx and blocks on the condition variable .Fa cond until a thread is signalled by a call to .Fn cnd_signal or .Fn cnd_broadcast or timeout .Fa ts has been reached. The .Fa ts parameter is specified as .Dv TIME_UTC based calendar time. If the mutex is not locked by the calling thread then behavior is undefined.
p The .Fn cnd_wait function atomically unlocks the mutex .Fa mtx and tries to block on the conditional variable .Fa cond until a thread is signalled by a call to .Fn cnd_signal or .Fn cnd_broadcast . The .Fa mtx mutex is locked again before the function returns. If the mutex is not locked by the calling thread then behavior is undefined. .Sh RETURN VALUES The .Fn cnd_broadcast function returns .Dv thrd_success on success or .Dv thrd_error on failure.
p The .Fn cnd_destroy function returns no value.
p The .Fn cnd_init function returns .Dv thrd_success on success or .Dv thrd_error on failure.
p The .Fn cnd_signal function returns .Dv thrd_success on success or .Dv thrd_error on failure.
p The .Fn cnd_timedwait function returns .Dv thrd_success on success, otherwise .Dv thrd_timedout to indicate that system time has reached or exceeded the time specified in .Dv ts , or .Dv thrd_error on failure.
p The .Fn cnd_wait function returns .Dv thrd_success on success or .Dv thrd_error on failure. .Sh SEE ALSO .Xr pthread_cond 3 , .Xr threads 3 .Sh STANDARDS The .Nm interface conforms to .St -isoC-2011 . .Sh HISTORY This interface first appeared in .Nx 9 . .Sh AUTHORS .An Kamil Rytarowski Aq Mt kamil@NetBSD.org