ttyname(3) Library Functions Manual ttyname(3)
NAME
ttyname, isatty, ttyname_r - Get the name of a terminal
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <unistd.h>
char *ttyname(
int file-descriptor);
int isatty(
int file-descriptor);
int ttyname_r(
int file-descriptor,
char *buffer,
int len);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
ttyname_r(): POSIX.1c
isatty(), ttyname(): XSH4.2
Refer to the standards(5) reference page for more information about industry standards and associated tags.
PARAMETERS
Specifies an open file descriptor. Points to a buffer in which the terminal name is stored. Specifies the length of the buffer pointed to
by the buffer parameter.
DESCRIPTION
The ttyname() function gets the name of a terminal. It returns a pointer to a string containing the null-terminated pathname of the termi-
nal device associated with the file-descriptor parameter.
The isatty() function determines if the device associated with the file-descriptor parameter is a terminal.
NOTES
The ttyname() function returns a pointer to thread-specific data. Subsequent calls to this function from the same thread overwrite this
data.
RETURN VALUES
Upon successful completion, the ttyname() function returns a pointer to a string identifying a terminal device. A NULL pointer is returned
if the file-descriptor parameter does not describe a terminal device in the /dev directory.
Upon successful completion, the isatty() function returns a value of 1 if the specified file-descriptor parameter is associated with a ter-
minal. Otherwise, it returns a value of zero (0).
[POSIX] Upon successful completion, the ttyname_r() function stores the terminal name as a null-terminated string in the buffer pointed to
by the buffer parameter and returns a value of 0 (zero). Otherwise, it returns an error number.
[Tru64 UNIX] The obsolete version of ttyname_r() functions the same way as the POSIX version, except it returns a -1 upon unsuccessful
completion.
ERRORS
If the isatty() function fails, errno may be set to the following value: The file associated with file-descriptor is not a terminal.
If the ttyname_r() function fails, errno may be set to the following value: The buffer parameter is a null pointer or the len parameter was
too short to store the string.
RELATED INFORMATION
Functions: ttyslot(3)
Standards: standards(5) delim off
ttyname(3)
