grantpt —
grant access to a slave pseudo-terminal device
Standard C Library (libc, -lc)
#include <stdlib.h>
int
grantpt(int
fildes);
The grantpt() function changes the mode and ownership of
the slave pseudo-terminal device that corresponds to the master
pseudo-terminal device associated with fildes to be
owned by the real user id of the calling process, group id of
tty. The permissions are set to readable and writable
by owner, and writable by group. If the slave pseudo-terminal device was being
accessed by other file descriptors at the time, all such access will be
revoked.
If successful, grantpt() returns 0; otherwise a value of
-1 is returned and errno is set to indicate the error.
The grantpt() function will fail if:
- [
EACCESS]
- the corresponding pseudo-terminal device could not be accessed.
- [
EBADF]
- fildes is not a valid descriptor.
- [
EINVAL]
- fildes is not associated with a master
pseudo-terminal device.
Setting the group to tty and revoking accesses by other
file descriptors are NetBSD extensions. Calling
grantpt() is equivalent to:
ioctl(fildes, TIOCGRANTPT, 0);
The grantpt() function conforms to IEEE
Std 1003.1-2001 (“POSIX.1”). Its first release was in
X/Open Portability Guide Issue 4, Version 2
(“XPG4.2”).