 unix pipe <code>./o | ./i</code></p>

<h4>o.c</h4>
<pre>
#include &lt;stdio.h&gt;

int
main()
{
	printf("(output hello)");
	return 0;
}
</pre>

<h4>i.c</h4>

<pre>
#include &lt;stdio.h&gt;

int
main()
{
	char line[256];
	if(fgets(line, 256, stdin) != NULL) {
		printf("(input: %s)\n", line);
	}
	return 0;
}
</pre>

<h3>Threads</h3>

<p>Threads are a way that a program can spawn concurrent operations that can then be delegated by the operating system to multiple processing cores. </p>

<pre>cc threads.c -o t