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unlockpt(S-osr5)


unlockpt -- unlock a pseudo-terminal master/slave pair

Syntax

cc ...-lc

#include <stdlib.h>

int unlockpt(int fildes);

Description

The function unlockpt(S-osr5) clears a lock flag for the slave pseudo-terminal associated with a master pseudo-terminal, so that the slave can be opened. fildes is a file descriptor referring to a master pseudo-terminal device.

Portable applications must call unlockpt( ) before opening the slave side of a pseudo-terminal device.

Return values

On successful completion, the function unlockpt( ) returns 0; otherwise it returns -1 and sets errno.

Diagnostics

unlockpt( ) fails if fildes is not an open file descriptor or is not associated with a master pseudo-terminal device. Diagnostic codes for this function are described below.

[EBADF]
Either the file descriptor refers to no open file, or the routine tried to write to a read-only file.

[EINVAL]
The file descriptor is not associated with a master pseudo-terminal device.

See also

grantpt(S-osr5), open(S-osr5), ptsname(S-osr5)

Standards conformance

unlockpt(S-osr5) is conformant with:

X/Open CAE Specification, System Interfaces and Headers, Issue 4, Version 2.


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SCO OpenServer Release 6.0.0 -- 02 June 2005