tcgetpgrp
pid_t tcgetpgrp(int);
tc_pgid = tcgetpgrp(STDOUT_FILENO);
while (tcgetpgrp(STDOUT_FILENO) != getpid())
tc_pgid = tcgetpgrp(STDOUT_FILENO);
my_tgid = tcgetpgrp(1);
pid_t current = tcgetpgrp(0);
if (tcgetattr(0, &mystty) == -1 || (svtgid = tcgetpgrp(0)) == -1) {
if (tcgetpgrp(fd) == getpgrp()) {
extern pid_t tcgetpgrp(int);