ctermid(3C)						   Standard C Library Functions 					       ctermid(3C)

NAME

       ctermid, ctermid_r - generate path name for controlling terminal

SYNOPSIS

       #include <stdio.h>

       char *ctermid(char *s);

       char *ctermid_r(char *s);

DESCRIPTION

   ctermid()
       The ctermid() function generates the path name of the controlling terminal for the current process and stores it in a string.

       If s is a null pointer, the string is stored in an internal static area whose address is returned and whose contents are overwritten at the
       next call to ctermid(). Otherwise, s is assumed to point to a character array of at least L_ctermid elements. The path name  is	placed	in
       this array and the value of s is returned. The constant L_ctermid is defined in the header <stdio.h>.

   ctermid_r()
       The ctermid_r() function behaves as ctermid() except that if s is a null pointer, the function returns NULL.

USAGE

       The difference between ctermid() and ttyname(3C) is that ttyname() must be passed a file descriptor and returns the actual name of the ter-
       minal associated with that file descriptor, while ctermid() returns a string (/dev/tty) that will refer to the terminal if used as  a  file
       name. The ttyname() function is useful only if the process already has at least one file open to a terminal.

       The ctermid() function is unsafe in multithreaded applications.	The ctermid_r() function is MT-Safe and should be used instead.

       When  compiling	multithreaded  applications, the  _REENTRANT flag must be defined on the compile line.	This flag should be used only with
       multithreaded applications.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |ctermid() is Standard	   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |ctermid() is Unsafe;  cter-  |
       |			     |mid_r() is MT-Safe	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ttyname(3C), attributes(5)

SunOS 5.11							    25 Jul 2000 						       ctermid(3C)