"__LINE__ and __FILE__ - (nf)"

[dap1 at ihlpf.UUCP]

#N:ihlpf:18400004:  0:395
ihlpf!dap1    Nov  1 16:25:00 1983

I just found that __LINE__ and __FILE__ contain the line number and file
currently being executed.  Since they don't need to be declared, they must
be evaluated by the compiler (along the lines of sizeof()).  Is this a
standard feature of C and if not, how widespread is it?

                                                 Darrell Plank
                                                 BTL-IH