ctermid (3p)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAME
ctermid — generate a pathname for the controlling terminalSYNOPSIS
#include <stdio.h>
char *ctermid(char * s);
DESCRIPTION
The ctermid() function shall generate a string that, when used as a pathname, refers to the current controlling terminal for the current process. If ctermid() returns a pathname, access to the file is not guaranteed. The ctermid() function need not be thread-safe if called with a NULL parameter.RETURN VALUE
If s is a null pointer, the string shall be generated in an area that may be static, the address of which shall be returned. The application shall not modify the string returned. The returned pointer might be invalidated or the string content might be overwritten by a subsequent call to ctermid(). If s is not a null pointer, s is assumed to point to a character array of at least L_ctermid bytes; the string is placed in this array and the value of s shall be returned. The symbolic constant L_ctermid is defined in <stdio.h>, and shall have a value greater than 0. The ctermid() function shall return an empty string if the pathname that would refer to the controlling terminal cannot be determined, or if the function is unsuccessful.ERRORS
No errors are defined. The following sections are informative.EXAMPLES
Determining the Controlling Terminal for the Current Process
The following example returns a pointer to a string that identifies the controlling terminal for the current process. The pathname for the terminal is stored in the array pointed to by the ptr argument, which has a size of L_ctermid bytes, as indicated by the term argument.#include <stdio.h> ... char term[L_ctermid]; char *ptr;
ptr = ctermid(term);