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POExecuting consecutive processes with execl()
 

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    <p>I have what is hopefully a simple question. I'd like to execute three programs called "brute_seq", "brute_pth" and "brute_omp" consecutively; basically execute "brute_seq", wait until it's finished, then execute "brute_pth" and same thing for "brute_omp".</p> <p>I've tried doing this several different ways and so far, the best solution I've come up with is this, although it's not quite what I need.</p> <pre><code>#include &lt;unistd.h&gt; int main() { if(fork() == 0) execl("brute_seq", (const char*)NULL, (char*)NULL); if(fork() == 0) execl("brute_pth", (const char*)NULL, (char*)NULL); if(fork() == 0) execl("brute_omp", (const char*)NULL, (char*)NULL); return 0; } </code></pre> <p>From what I understand, the forked process will run the execl() command, which in turn will replace the forked process with the called process - this insures that my forked process terminates when the called process ends. </p> <p>I have two problems with this implementation:</p> <ol> <li>The processes do not execute sequentially, but in parallel, which I don't want.</li> <li>Once they're all done executing, my terminal blocks in a similar way that it would block when encountering a deadlock due to poor synchronization, except worse, because I can't CTRL-Z out of it; I have to exit from the terminal and open it again.</li> </ol> <p>Any ideas?</p> <hr> <p>Thanks to Joachim's helpful tip, here's the working code that does exactly what I want:</p> <pre><code>#include &lt;sys/wait.h&gt; #include &lt;unistd.h&gt; int main() { pid_t child_pid; int status; if((child_pid = fork()) == 0) execl("brute_seq", (const char*)NULL, (char*)NULL); else { waitpid(child_pid, &amp;status, 0); if((child_pid = fork()) == 0) { execl("brute_pth", (const char*)NULL, (char*)NULL); } waitpid(child_pid, &amp;status, 0); execl("brute_omp", (const char*)NULL, (char*)NULL); } return 0; } </code></pre>
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