PG_DIAG_STATEMENT_POSITION Where is it defined?

I have been searching through the cvs web browser for about 1/2 hour and
can't find where PG_DIAG_STATEMENT_POSITION
is defined.

I need to know the integer value of the constant(pascal talk)/Symbol (c
talk) so I can add it to my Delphi client library.

Thanks in advance

--
Tony