The Open Group Base Specifications Issue 8
IEEE Std 1003.1-2024
Copyright © 2001-2024 The IEEE and The Open Group

NAME

unlockpt — unlock a pseudo-terminal manager/subsidiary pair

SYNOPSIS

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

int unlockpt(int
fildes); [Option End]

DESCRIPTION

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

Conforming applications shall ensure that they call unlockpt() before opening the subsidiary 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 manager 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.

Issue 8

Austin Group Defect 1466 is applied, changing the terminology used for pseudo-terminal devices.

End of informative text.

 

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