grantpt(3) -- Linux man page

 

NAME

grantpt - grant access to the slave pseudotty  

SYNOPSIS

#include <stdlib.h>

int grantpt(int fd);
 

DESCRIPTION

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.  

RETURN VALUE

When successful, grantpt() returns 0. Otherwise, it returns -1 and sets errno appropriately.  

ERRORS

EBADF
The fd argument is not a valid open file descriptor.
EINVAL
The fd argument is valid but not associated with a master pty.
EACCES
The corresponding slave pty could not be accessed.
 

CONFORMING TO

POSIX 1003.1-2001  

NOTES

This is part of the Unix98 pty support, see pts(4). Many systems implement this function via a setuid helper binary called "pt_chown". With Linux devpts no such helper binary is required.  

SEE ALSO

open(2), getpt(3), ptsname(3), unlockpt(3), pts(4)