tcgetpgrp
if (tcgetpgrp(0) == getpid())
initialpgrp = tcgetpgrp(ttyfd);
return (getpgrp() == tcgetpgrp(STDOUT_FILENO));
pid_t tcgetpgrp(int);
pid_t tcgetpgrp(int);
if (tcgetpgrp(STDERR_FILENO) == getpgrp())
if (tcgetpgrp(STDERR_FILENO) == child_pgrp)
if (tcgetpgrp(STDERR_FILENO) == getpgrp()) {
tcgetpgrp(fd[0]) == getpgrp();
newsid = tcgetpgrp(p->fd) == getpgrp();
tcgetpgrp(p->fd) == getpgrp())
return tcgetpgrp(p->fd_in);