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 grantpt(int fildes);
The grantpt() function shall change the mode and ownership of the slave pseudo-terminal device associated with its master pseudo-terminal counterpart. The fildes argument is a file descriptor that refers to a master pseudo-terminal device. The user ID of the slave shall be set to the real UID of the calling process and the group ID shall be set to an unspecified group ID. The permission mode of the slave pseudo-terminal shall be set to readable and writable by the owner, and writable by the group.
The behavior of the grantpt() function is unspecified if the application has installed a signal handler to catch SIGCHLD signals.
Upon successful completion, grantpt() shall return 0; otherwise, it shall return -1 and set errno to indicate the error.
The grantpt() function may fail if:
The corresponding slave pseudo-terminal device could not be accessed.
The fildes argument is not a valid open file descriptor.
The fildes argument is not associated with a master pseudo-terminal device.
The following sections are informative.
See the RATIONALE section for posix_openpt().
open(), posix_openpt(), ptsname(), unlockpt()
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 .
posix_openpt(3p), ptsname(3p), stdlib.h(0p), unlockpt(3p).