ptsname(3) Library Functions Manual ptsname(3)
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 de-
vice 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 re-
turned 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)
Linux man-pages 6.9.1 2024-05-02 ptsname(3)
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