PTSNAME

Section: Linux Programmer's Manual (3)
Updated: 2020-06-09
Page Index

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 ||
        (_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED)
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.

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.

COLOPHON

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