freebsd man page for tcgetpgrp

TCGETPGRP(3)						   BSD Library Functions Manual 					      TCGETPGRP(3)

NAME
     tcgetpgrp -- get foreground process group ID

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/types.h>
     #include <unistd.h>

     pid_t
     tcgetpgrp(int fd);

DESCRIPTION
     The tcgetpgrp() function returns the value of the process group ID of the foreground process group associated with the terminal device.  If
     there is no foreground process group, tcgetpgrp() returns an invalid process ID.

ERRORS
     If an error occurs, tcgetpgrp() returns -1 and the global variable errno is set to indicate the error, as follows:

     [EBADF]		The fd argument is not a valid file descriptor.

     [ENOTTY]		The calling process does not have a controlling terminal or the underlying terminal device represented by fd is not the
			controlling terminal.

SEE ALSO
     setpgid(2), setsid(2), tcsetpgrp(3)

STANDARDS
     The tcgetpgrp() function is expected to be compliant with the IEEE Std 1003.1-1988 (``POSIX.1'') specification.

BSD
								   June 4, 1993 							       BSD