ptsname, ptsname_r - get the name of the slave pseudoterminal
#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
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.
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.
(ptsname_r() only) buf is NULL. (This error is returned only for glibc 2.25 and earlier.)
fd does not refer to a pseudoterminal master device.
(ptsname_r() only) buf is too small.
ptsname() is provided in glibc since version 2.1.
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 |
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.
grantpt(3), posix_openpt(3), ttyname(3), unlockpt(3), pts(4), pty(7)
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