ptsname(3)

1ptsname(3)                 Library Functions Manual                 ptsname(3)
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NAME

6       ptsname, ptsname_r - get the name of the slave pseudoterminal
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <stdlib.h>
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14       char *ptsname(int fd);
15       int ptsname_r(int fd, char buf[.buflen], size_t buflen);
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       ptsname():
20           Since glibc 2.24:
21               _XOPEN_SOURCE >= 500
22           glibc 2.23 and earlier:
23               _XOPEN_SOURCE
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25       ptsname_r():
26           _GNU_SOURCE
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DESCRIPTION

29       The ptsname() function returns the name of the slave pseudoterminal de‐
30       vice corresponding to the master referred to by the file descriptor fd.
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32       The ptsname_r() function is the reentrant equivalent of ptsname().   It
33       returns  the  name  of the slave pseudoterminal device as a null-termi‐
34       nated string in the buffer pointed to  by  buf.   The  buflen  argument
35       specifies the number of bytes available in buf.
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RETURN VALUE

38       On  success,  ptsname() returns a pointer to a string in static storage
39       which will be overwritten by subsequent calls.  This pointer  must  not
40       be freed.  On failure, NULL is returned.
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42       On  success, ptsname_r() returns 0.  On failure, an error number is re‐
43       turned to indicate the error.
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ERRORS

46       EINVAL (ptsname_r() only) buf is NULL.  (This error  is  returned  only
47              for glibc 2.25 and earlier.)
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49       ENOTTY fd does not refer to a pseudoterminal master device.
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51       ERANGE (ptsname_r() only) buf is too small.
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ATTRIBUTES

54       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
55       tributes(7).
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57       ┌─────────────────────────────┬───────────────┬────────────────────────┐
58       │Interface                    │ Attribute     │ Value                  │
59       ├─────────────────────────────┼───────────────┼────────────────────────┤
60       │ptsname()                    │ Thread safety │ MT-Unsafe race:ptsname │
61       ├─────────────────────────────┼───────────────┼────────────────────────┤
62       │ptsname_r()                  │ Thread safety │ MT-Safe                │
63       └─────────────────────────────┴───────────────┴────────────────────────┘
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VERSIONS

66       A version of ptsname_r() is documented on Tru64 and HP-UX, but on those
67       implementations,  -1  is  returned on error, with errno set to indicate
68       the error.  Avoid using this function in portable programs.
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STANDARDS

71       ptsname():
72              POSIX.1-2008.
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74       ptsname_r() is a Linux extension, that is proposed for inclusion in the
75       next major revision of POSIX.1 (Issue 8).
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HISTORY

78       ptsname():
79              POSIX.1-2001.  glibc 2.1.
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81       ptsname() is part of the UNIX 98 pseudoterminal support (see pts(4)).
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