osf1 man page for isatty

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)