PTSNAME(3)                                                              Linux Programmer's Manual                                                             PTSNAME(3)

NAME
       ptsname, ptsname_r - get the name of the slave pseudoterminal

SYNOPSIS
       #include <stdlib.h>

       char *ptsname(int fd);
       int ptsname_r(int fd, char *buf, size_t buflen);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       ptsname():
           Since glibc 2.24:
               _XOPEN_SOURCE >= 500
           Glibc 2.23 and earlier:
               _XOPEN_SOURCE

       ptsname_r():
           _GNU_SOURCE

DESCRIPTION
       The ptsname() function returns the name of the slave pseudoterminal device corresponding to the master referred to by the file descriptor fd.

       The  ptsname_r()  function  is  the reentrant equivalent of ptsname().  It returns the name of the slave pseudoterminal device as a null-terminated string in the
       buffer pointed to by buf.  The buflen argument specifies the number of bytes available in buf.

RETURN VALUE
       On success, ptsname() returns a pointer to a string in static storage which will be overwritten by subsequent calls.  This pointer must not be freed.   On  fail‐
       ure, NULL is returned.

       On success, ptsname_r() returns 0.  On failure, an error number is returned to indicate the error.

ERRORS
       EINVAL (ptsname_r() only) buf is NULL.  (This error is returned only for glibc 2.25 and earlier.)

       ENOTTY fd does not refer to a pseudoterminal master device.

       ERANGE (ptsname_r() only) buf is too small.

VERSIONS
       ptsname() is provided in glibc since version 2.1.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬────────────────────────┐
       │Interface                                                                                                              │ Attribute     │ Value                  │
       ├───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼────────────────────────┤
       │ptsname()                                                                                                              │ Thread safety │ MT-Unsafe race:ptsname │
       ├───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼────────────────────────┤
       │ptsname_r()                                                                                                            │ Thread safety │ MT-Safe                │
       └───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴────────────────────────┘

CONFORMING TO
       ptsname():
        POSIX.1-2001, POSIX.1-2008.

       ptsname() is part of the UNIX 98 pseudoterminal support (see pts(4)).

       ptsname_r()  is  a  Linux extension, that is proposed for inclusion in the next major revision of POSIX.1 (Issue 8).  A version of this function is documented on
       Tru64 and HP-UX, but on those implementations, -1 is returned on error, with errno set to indicate the error.  Avoid using this function in portable programs.

SEE ALSO
       grantpt(3), posix_openpt(3), ttyname(3), unlockpt(3), pts(4), pty(7)

                                                                               2021-03-22                                                                     PTSNAME(3)