This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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 .

IEEE/The Open Group                                   2017                                       PTSNAME(3POSIX)

       The ptsname() function shall return the name of the slave pseudo-terminal device associated with a master
       pseudo-terminal  device.  The  fildes argument is a file descriptor that refers to the master device. The
       ptsname() function shall return a pointer to a string containing the pathname of the corresponding  slave
       device.

       The ptsname() function need not be thread-safe.

       The ptsname() function may fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       ENOTTY The file associated with the fildes argument is not a master pseudo-terminal device.

       Thefollowingsectionsareinformative.

       None.

       None.

       ptsname — get name of the slave pseudo-terminal device

       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.

       See the RATIONALE section for posix_openpt().

       Upon successful completion, ptsname() shall return a pointer to a string which is the name of the pseudo-
       terminal slave device. Upon failure, ptsname() shall return a null pointer and may set errno.  This could
       occur  if  fildes  is  an  invalid file descriptor or if the slave device name does not exist in the file
       system.

       The application shall not modify the string returned. The returned pointer might be  invalidated  or  the
       string  content  might  be  overwritten  by a subsequent call to ptsname().  The returned pointer and the
       string content might also be invalidated if the calling thread is terminated.

grantpt(), open(), posix_openpt(), ttyname(), unlockpt()

       The Base Definitions volume of POSIX.1‐2017, <stdlib.h>

       #include <stdlib.h>

       char *ptsname(int fildes);