NAME¶

grantpt - grant access to the slave pseudo-terminal

SYNOPSIS¶

#define _XOPEN_SOURCE


#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¶

EACCES

The corresponding slave pty could not be accessed.

EBADF

The fd argument is not a valid open file descriptor.

EINVAL

The fd argument is valid but not associated with a master pty.

VERSIONS¶

grantpt() is provided in glibc since version 2.1.

CONFORMING TO¶

POSIX.1-2001.

NOTES¶

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.

SEE ALSO¶

open(2), posix_openpt(3), ptsname(3), unlockpt(3), pts(4), feature_test_macros(7), pty(7)

COLOPHON¶

This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.