Of pipes, dups, and forks

It has been a long time since I used pipes, I/O duplication, and process forking in a C program. However, I need to remember how it is done. The UNIX command ls | wc is implemented this way in C.

pipe(p);

if ((pid1 = fork()) == 0) {
close(p[1]);
dup2(p[0],0);
close(p[0]);
execl("wc","wc",(char *)0);
exit(1);
}
if ((pid1 = fork()) == 0) {
close(p[0]);
dup2(p[1],1);
close(p[1]);
execl("ls","ls",(char *)0);
exit(1);
}
close(p[0]);
close(p[1]);

while(wait(&status) != pid1);