This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
#include <stdlib.h> int unlockpt(int fildes);
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.
Upon successful completion, unlockpt() shall return 0. Otherwise, it shall return -1 and set errno to indicate the error.
The unlockpt() function may fail if:
The fildes argument is not a file descriptor open for writing.
The fildes argument is not associated with a master pseudo-terminal device.
The following sections are informative.
See the RATIONALE section for posix_openpt().
grantpt(), open(), posix_openpt(), ptsname()
The Base Definitions volume of POSIX.1-2017, <stdlib.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
grantpt(3p), open(3p), posix_openpt(3p), ptsname(3p), stdlib.h(0p).