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grantpt(3) [linux man page]

GRANTPT(3)						     Linux Programmer's Manual							GRANTPT(3)

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 3.27 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/. GNU
2008-06-14 GRANTPT(3)

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GRANTPT(3)						     Linux Programmer's Manual							GRANTPT(3)

NAME
grantpt - grant access to the slave pseudoterminal SYNOPSIS
#include <stdlib.h> int grantpt(int fd); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): grantpt(): Since glibc 2.24: _XOPEN_SOURCE >= 500 || (_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) Glibc 2.23 and earlier: _XOPEN_SOURCE 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 | +----------+---------------+----------------+ CONFORMING TO
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". 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 (posix_openpt(3)), so that nothing must be done by grantpt(). 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). SEE ALSO
open(2), posix_openpt(3), ptsname(3), unlockpt(3), pts(4), pty(7) COLOPHON
This page is part of release 4.15 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/. GNU
2017-09-15 GRANTPT(3)

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