SYNOPSIS
#include <nng/nng.h>
#include <nng/supplemental/util/platform.h>
int nng_cv_wait(nng_cv *cv, nng_time when);DESCRIPTION
The nng_cv_until() waits until either the condition variable cv is signaled
by another thread calling either nng_cv_wake() or
nng_cv_wake1(), or the system clock (as tracked
by nng_clock()) reaches when.
The caller must have have ownership of the mutex that was used when cv was allocated. This function will drop the ownership of that mutex, and reacquire it atomically just before returning to the caller. (The waiting is done without holding the mutex.)
| Any condition may be used or checked, but the condition must be checked, as it is possible for this function to wake up “spuriously”. The best way to do this is inside a loop that repeats until the condition tests for true. |
EXAMPLE
The following example demonstrates use of this function:
Example 1: Waiting for the condition
nng_mtx_lock(m); // assume cv was allocated using m
while (!condition_true) {
if (nng_cv_wait(cv) == NNG_ETIMEDOUT) {
printf("Time out reached!\n");
break;
}
}
// condition_true is true
nng_mtx_unlock(m);Example 2: Signaling the condition
nng_mtx_lock(m);
condition_true = true;
cv_wake(cv);
nng_mtx_unlock(m);RETURN VALUES
None.
ERRORS
None.