char *ptsname(int fildes);
The ptsname() function shall return the name of the slave pseudo-terminal device associated with a master pseudo-terminal device. The fildes argument is a file descriptor that refers to the master device. The ptsname() function shall return a pointer to a string containing the pathname of the corresponding slave device.
The ptsname() function need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.
Upon successful completion, ptsname() shall return a pointer to a string which is the name of the pseudo-terminal slave device. Upon failure, ptsname() shall return a null pointer. This could occur if fildes is an invalid file descriptor or if the slave device name does not exist in the file system.
No errors are defined.
The following sections are informative.
The value returned may point to a static data area that is overwritten by each call to ptsname().
grantpt() , open() , ttyname() , unlockpt() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>