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  1. PO
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    <p>All, I have solved this problem very, very easily. I am embarrassed for not catching this sooner, but I took a break from this code for a while. The solution is so trivial. All that was needed was an extra condition variable that the generator waits on until the monitor is finished. Here is the code.</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;math.h&gt; #include &lt;pthread.h&gt; #include &lt;time.h&gt; int square_root; volatile int is_square = 0; int done = 0; int count = 0; //used to count how many perfect squares generator_func finds int count1 = 0; //used to compare how many responses monitor makes to signal pthread_mutex_t mutex; pthread_cond_t mon, gen; void* generator_func(void* args){ srand(time(NULL)); int i, temp, sq; for(i = 0; i&lt;1000; i++){ temp = rand() % 10000; sq = sqrt((double)temp); if((pow(sq,2)) == temp){ pthread_mutex_lock(&amp;mutex); count++; square_root = sq; is_square = 1; fprintf(stderr, "Square root of %d is", temp); pthread_cond_signal(&amp;mon); //signal monitor pthread_cond_wait(&amp;gen, &amp;mutex); //wait for monitor to finish *Solution* pthread_mutex_unlock(&amp;mutex); } } pthread_mutex_lock(&amp;mutex); done = 1; is_square = -1; pthread_cond_signal(&amp;mon); pthread_mutex_unlock(&amp;mutex); } main(){ pthread_t generator; //declare thread pthread_mutex_init(&amp;mutex, NULL); //initialize mutex pthread_cond_init(&amp;mon, NULL); //initialize condition var for monitor pthread_cond_init(&amp;gen, NULL); //initialize condition var for generator pthread_create(&amp;generator, NULL, generator_func, NULL); //create thread //monitor pthread_mutex_lock(&amp;mutex); while(done != 1 || is_square == 1){ while(is_square == 0){ pthread_cond_wait(&amp;mon, &amp;mutex); } if(is_square == 1 &amp;&amp; done != 1){ count1++; fprintf(stderr, " %d\n", square_root); is_square = 0; } pthread_cond_signal(&amp;gen); //start generator back up *Solution* } pthread_mutex_unlock(&amp;mutex); pthread_join(generator, NULL); printf("%d %d\n", count, count1); //shows inconsistency between generator and monitor pthread_mutex_destroy(&amp;mutex); pthread_cond_destroy(&amp;mon); } </code></pre>
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    1. POSimple Generator-monitor program with condition variables
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    1. USTrevor Arjeski
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    1. This table or related slice is empty.
    1. POSimple Generator-monitor program with condition variables
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    1. VO
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      1. VTAcceptedByOriginator
    1. COBe aware that your solution will force a context switch after *every* found root. Your program is now correct, but will be very slow.
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    2. CO@thiton of course. I would hope correctness supersedes performance though!
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      1. USTrevor Arjeski
 

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