May 25, 2004 UNLOCKPT 3

### NAME

unlockpt - unlock the slave pseudo-terminal device

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` unlockpt(```int fildes`)

### DESCRIPTION

The unlockpt(``) unlocks access to the pseudo-terminal device corresponding to the master pseudo-terminal device associated with ```fildes`. Conforming applications must call this function before opening the slave pseudo-terminal device.

### RETURN VALUES

If successful, unlockpt(``) returns 0; otherwise a value of -1 is returned and errno is set to indicate the error.

### ERRORS

The unlockpt(``) 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.

### NOTES

In NetBSD unlockpt(``) does nothing.

### SEE ALSO

ioctl(2), grantpt(3), posix_openpt(3), ptsname(3)

### STANDARDS

The unlockpt(``) 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'') .