tcgetpgrp - get foreground process group ID

Syntax	#include <unistd.h> Optional #include <sys/types.h> (End) pid_t tcgetpgrp(int fildes);
Description	tcgetpgrp() returns the value of the foreground process group ID associated with the terminal. If there is no foreground process group, tcgetpgrp() returns a value greater than 1 that does not match the process group ID of any existing process group. tcgetpgrp() is allowed from a process that is a member of a background process group; however, the information may be subsequently changed by a process that is a member of a foreground process group.
Return val.	Value of the foreground process group ID associated with the terminal
		if successful.
	-1	if an error occurs. errno is set to indicate the error.
Errors	tcgetpgrp() will fail if:
	EBADF	fildes is not a valid file descriptor.
	Extension
	EINVAL	An attempt was made to access a BS2000 file. (End)
	ENOTTY	The calling process does not have a controlling terminal, or the file is not the controlling terminal.
See also	setsid(), setpgid(), tcsetpgrp(), sys/types.h, unistd.h.