grantpt — grant access to the slave pseudo-terminal
#define _XOPEN_SOURCE #include <stdlib.h>
int grantpt( |
int fd); |
The grantpt() function
changes the mode and owner of the slave pseudo-terminal
device (pty) corresponding to the master pty referred to by
fd. The user ID of
the slave is set to the real UID of the calling process. The
group ID is set to an unspecified value (e.g., tty). The mode of the slave is set to 0620
(crw−−w−−−−).
The behavior of grantpt() is
unspecified if a signal handler is installed to catch
SIGCHLD signals.
When successful, grantpt()
returns 0. Otherwise, it returns −1 and sets
errno appropriately.
The corresponding slave pty could not be accessed.
The fd
argument is not a valid open file descriptor.
The fd
argument is valid but not associated with a master
pty.
This is part of the Unix98 pty support, see pts(4). Many systems implement this function via a set-user-ID helper binary called "pt_chown". With Linux devpts no such helper binary is required.