NAME

       ptsname, ptsname_r - get the name of the slave pseudoterminal

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <stdlib.h>

       char *ptsname(int fd);
       int ptsname_r(int fd, char buf[.buflen], 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 failure, 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.

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                │
       └────────────────────────────────────────────────┴───────────────┴────────────────────────┘

VERSIONS

       A version of ptsname_r() 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.

STANDARDS

       ptsname():
              POSIX.1-2008.

       ptsname_r() is a Linux extension, that  is  proposed  for  inclusion  in  the  next  major
       revision of POSIX.1 (Issue 8).

HISTORY

       ptsname():
              POSIX.1-2001.  glibc 2.1.

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

SEE ALSO

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