Section: Linux Programmer's Manual (3)
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grantpt - grant access to the slave pseudoterminal
int grantpt(int fd);
Feature Test Macro Requirements for glibc (see
Since glibc 2.24:
_XOPEN_SOURCE >= 500 ||
(_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED)
Glibc 2.23 and earlier:
function changes the mode and owner of the slave pseudoterminal device
corresponding to the master pseudoterminal referred to by
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.,
The mode of the slave is set to 0620 (crw--w----).
The behavior of
is unspecified if a signal handler is installed to catch
Otherwise, it returns -1 and sets
The corresponding slave pseudoterminal could not be accessed.
argument is not a valid open file descriptor.
argument is valid but not associated with a master pseudoterminal.
is provided in glibc since version 2.1.
For an explanation of the terms used in this section, see
||Thread safety||MT-Safe locale|
This is part of the UNIX 98 pseudoterminal support, see
Many systems implement this function via a set-user-ID helper binary
On Linux systems with a devpts filesystem (present since Linux 2.2),
the kernel normally sets the correct ownership and permissions
for the pseudoterminal slave when the master is opened
so that nothing must be done by
Thus, no such helper binary is required
(and indeed it is configured to be absent during the
glibc build that is typical on many systems).
This page is part of release 4.15 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
- RETURN VALUE
- CONFORMING TO
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This document was created by
using the manual pages.
Time: 19:14:24 GMT, September 19, 2018