NAME¶
grantpt - grant access to the slave pseudoterminal
SYNOPSIS¶
#define _XOPEN_SOURCE /* See feature_test_macros(7) */
#include <stdlib.h>
int grantpt(int fd);
DESCRIPTION¶
The
grantpt() function changes the mode and owner of the slave
pseudoterminal device corresponding to the master pseudoterminal 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 pseudoterminal 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
pseudoterminal.
VERSIONS¶
grantpt() is provided in glibc since version 2.1.
ATTRIBUTES¶
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| grantpt () |
Thread safety |
MT-Safe locale |
POSIX.1-2001, POSIX.1-2008.
NOTES¶
This is part of the UNIX 98 pseudoterminal 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),
pty(7)
COLOPHON¶
This page is part of release 4.10 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
