The Open Group Base Specifications Issue 7, 2018 edition
IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008)
Copyright © 2001-2018 IEEE and The Open Group
A newer edition of this document exists here

NAME

unlockpt - unlock a pseudo-terminal master/slave pair

SYNOPSIS

[XSI] [Option Start] #include <stdlib.h>

int unlockpt(int
fildes); [Option End]

DESCRIPTION

The unlockpt() function shall unlock the slave pseudo-terminal device associated with the master to which fildes refers.

Conforming applications shall ensure that they call unlockpt() before opening the slave side of a pseudo-terminal device.

RETURN VALUE

Upon successful completion, unlockpt() shall return 0. Otherwise, it shall return -1 and set errno to indicate the error.

ERRORS

The unlockpt() function may fail if:

[EBADF]
The fildes argument is not a file descriptor open for writing.
[EINVAL]
The fildes argument is not associated with a master pseudo-terminal device.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

See the RATIONALE section for posix_openpt.

FUTURE DIRECTIONS

None.

SEE ALSO

grantpt, open, posix_openpt, ptsname

XBD <stdlib.h>

CHANGE HISTORY

First released in Issue 4, Version 2.

Issue 5

Moved from X/OPEN UNIX extension to BASE.

Issue 6

The normative text is updated to avoid use of the term "must" for application requirements.

Issue 7

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0697 [96] is applied.

End of informative text.

 

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