NAME

unlockpt - Unlocks a pseudoterminal master and slave pair

LIBRARY

Standard C Library (libc.so, libc.a)

SYNOPSIS

#include <stdlib.h>

int unlockpt(
int mastfd);

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

unlockpt():  XPG4−UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

PARAMETERS

mastfdSpecifies a file descriptor that is returned from a successful open of the master pseudoterminal device. 

DESCRIPTION

The unlockpt() function unlocks a slave pseudoterminal from its associated master counterpart.  It does this by clearing a lock flag so that the slave device can be opened. 

RETURN VALUE

Upon successful completion, the unlockpt() function returns a value of 0.  Otherwise, it returns a value of -1 and sets errno to indicate the error. 

ERRORS

The unlockpt() function sets errno to the specified values for the following conditions:

[EBADF]The file descriptor specified by the mastfd parameter is not an open file descriptor. 

[EINVAL]The file descriptor specified by the mastfd parameter is not associated with a master pseudoterminal device. 

RELATED INFORMATION

Functions: openpty(3)

Standards: standards(5)

Guides: System V Compatibility User’s Guide