grantpt(3)grantpt(3)NAMEgrantpt - Permit access to the slave pseudoterminal device
SYNOPSIS
#include <stdlib.h>
int grantpt(
int fildes );
LIBRARY
Standard C Library (libc)
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
grantpt(): XPG4-UNIX
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
PARAMETERS
Specifies a file descriptor that is returned from a successful open of
a master pseudoterminal device.
DESCRIPTION
The grantpt() function modifies the ownership and mode of the slave
pseudoterminal device associated with its master pseudoterminal coun‐
terpart.
The modifications of mode and ownership are performed as follows: The
group ID is set to a reserved group. The slave user ID is set to the
real UID of the calling process. The permissions of the slave device
are set so that the owner is allowed read and write access and the
group is allowed write access.
RETURN VALUES
Upon successful completion, the grantpt() function returns a value of 0
(zero). Otherwise, it returns a value of -1 and sets errno to indicate
the error.
ERRORS
The grantpt() function sets errno to the specified values for the fol‐
lowing conditions:
The corresponding slave device cannot be accessed. The file descriptor
specified by the fildes parameter is not a valid open file descriptor.
The file descriptor specified by the fildes parameter is not associated
with a master device.
The grantpt() function may also fail if the application has installed a
signal handler to catch SIGCHLD (death of a child) signals.
Applications calling grantpt() may get a SIGCHLD signal from processes
that they did not explicitly create.
SEE ALSO
Functions: open(2), ptsname(3), setuid(2), unlockpt(3)
Standards: standards(5)grantpt(3)