Manpage of TCGETPGRP
TCGETPGRPSection: Linux Programmer's Manual (3)
NAMEtcgetpgrp, tcsetpgrp - get and set terminal foreground process group
pid_t tcgetpgrp(int fd);
DESCRIPTIONThe function tcgetpgrp() returns the process group ID of the foreground process group on the terminal associated to fd, which must be the controlling terminal of the calling process.
The function tcsetpgrp() makes the process group with process group ID pgrpthe foreground process group on the terminal associated to fd, which must be the controlling terminal of the calling process, and still be associated with its session. Moreover, pgrpmust be a (nonempty) process group belonging to the same session as the calling process.
If tcsetpgrp() is called by a member of a background process group in its session, and the calling process is not blocking or ignoring SIGTTOU, a SIGTTOUsignal is sent to all members of this background process group.
RETURN VALUEWhen fdrefers to the controlling terminal of the calling process, the function tcgetpgrp() will return the foreground process group ID of that terminal if there is one, and some value larger than 1 that is not presently a process group ID otherwise. When fddoes not refer to the controlling terminal of the calling process, -1 is returned, and errnois set appropriately.
- fdis not a valid file descriptor.
- pgrphas an unsupported value.
- The calling process does not have a controlling terminal, or it has one but it is not described by fd, or, for tcsetpgrp(), this controlling terminal is no longer associated with the session of the calling process.
- pgrphas a supported value, but is not the process group ID of a process in the same session as the calling process.
ATTRIBUTESFor an explanation of the terms used in this section, see attributes(7).
|tcgetpgrp(), tcsetpgrp()||Thread safety||MT-Safe|
CONFORMING TOPOSIX.1-2001, POSIX.1-2008.
NOTESThese functions are implemented via the TIOCGPGRPand TIOCSPGRPioctls.
HistoryThe ioctls appeared in 4.2BSD. The functions are POSIX inventions.
SEE ALSOsetpgid(2), setsid(2), credentials(7)
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