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   grantpt    ( 3 )

предоставить доступ к подчиненному псевдотерминалу (grant access to the slave pseudoterminal)

Имя (Name)

grantpt - grant access to the slave pseudoterminal

Синопсис (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 Glibc 2.23 and earlier: _XOPEN_SOURCE


Описание (Description)

The grantpt() function changes the mode and owner of the slave
       pseudoterminal device corresponding to the master pseudoterminal
       referred to by the file descriptor 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.


Возвращаемое значение (Return value)

When successful, grantpt() returns 0.  Otherwise, it returns -1
       and sets errno to indicate the error.

Ошибки (Error)

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.


Версии (Versions)

grantpt() is provided in glibc since version 2.1.

Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

┌───────────────────────────────┬───────────────┬────────────────┐ │Interface Attribute Value │ ├───────────────────────────────┼───────────────┼────────────────┤ │grantpt() │ Thread safety │ MT-Safe locale │ └───────────────────────────────┴───────────────┴────────────────┘


Стандарты (Conforming to)

POSIX.1-2001, POSIX.1-2008.

Примечание (Note)

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).


Смотри также (See also)

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