/* popen_ex3.c *	shows how to use popen to write to a process that *	reads from stdin.  This program writes email to *	two users.  Note how easy it is to use fprintf *	to format the data to send. */#include	<stdio.h>main(){	FILE	*fp;	fp = popen( "mail admin backup", "w" );	fprintf( fp, "Error with backup!!\n" );	pclose( fp );}