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POpthread_cond_wait for 2 threads
 

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    <p>I'm trying to implement <code>pthread_cond_wait</code> for 2 threads. My test code is trying to use two threads to preform the following scenario:</p> <ul> <li>Thread B waits for condition</li> <li>Thread A prints "Hello" five times</li> <li>Thread A signals thread B</li> <li>Thread A waits</li> <li>Thread B prints "Goodbye"</li> <li>Thread B signals thread A</li> <li>Loop to start (x5)</li> </ul> <p>So far the code prints "Hello" five times and then gets stuck. From examples I've looked at it seems I'm on the right track, "Lock mutex, wait, get signaled by other thread, unlock mutex, do stuff, loop"</p> <p>Test Code:</p> <pre><code>//Import #include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;pthread.h&gt; #include &lt;unistd.h&gt; //global variables pthread_cond_t condA = PTHREAD_COND_INITIALIZER; pthread_cond_t condB = PTHREAD_COND_INITIALIZER; pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; void *threadA() { int i = 0, rValue, loopNum; while(i&lt;5) { //unlock mutex rValue = pthread_mutex_unlock(&amp;mutex); //do stuff for(loopNum = 1; loopNum &lt;= 5; loopNum++) printf("Hello %d\n", loopNum); //signal condition of thread b rValue = pthread_cond_signal(&amp;condB); //lock mutex rValue = pthread_mutex_lock(&amp;mutex); //wait for turn while( pthread_cond_wait(&amp;condA, &amp;mutex) != 0 ) i++; } } void *threadB() { int n = 0, rValue; while(n&lt;5) { //lock mutex rValue = pthread_mutex_lock(&amp;mutex); //wait for turn while( pthread_cond_wait(&amp;condB, &amp;mutex) != 0 ) //unlock mutex rValue = pthread_mutex_unlock(&amp;mutex); //do stuff printf("Goodbye"); //signal condition a rValue = pthread_cond_signal(&amp;condA); n++; } } int main(int argc, char *argv[]) { //create our threads pthread_t a, b; pthread_create(&amp;a, NULL, threadA, NULL); pthread_create(&amp;b, NULL, threadB, NULL); pthread_join(a, NULL); pthread_join(b,NULL); } </code></pre> <p>A pointer in the right direction would be greatly appreciated, thanks! (Code compiled on Linux using "gcc timeTest.c -o timeTest -lpthread")</p>
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    1. CONo it is not required, I was mainly trying variations but as you said it would be ideal to only use one
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