grantpt (3)

#define _XOPEN_SOURCE       /* See feature_test_macros(7) */

#include <stdlib.h>

int grantpt(int fd);

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.

When successful, grantpt() returns 0. Otherwise, it returns -1 and sets errno appropriately.

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.

grantpt() is provided in glibc since version 2.1.

POSIX.1-2001.

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.

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

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