#define _XOPEN_SOURCE       /* See feature_test_macros(7) */

#include <stdlib.h>

char *ptsname(int fd);

#define _GNU_SOURCE         /* See feature_test_macros(7) */

#include <stdlib.h>

int ptsname_r(int fd, char *buf, size_t buflen);


The ptsname() function returns the name of the slave pseudoterminal device corresponding to the master referred to by 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, a nonzero value is returned and errno is set to indicate the error.



(ptsname_r() only) buf is NULL.


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.


Multithreading (see pthreads(7))

The ptsname() function is not thread-safe.

The ptsname_r() function is thread-safe.


ptsname() is part of the UNIX 98 pseudoterminal support (see pts(4)). This function is specified in POSIX.1-2001.

ptsname_r() is a Linux extension. 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.

RELATED TO ptsname…


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