Preprocessor equality test, is this standard?

Question

I had envisaged one of these in the project preferences

• TESTING = HOST
• TESTING = TARGET

Answer 1

#if TESTING==HOST

If TESTING is not defined, then

it is equivalent to:

#if 0==HOST

From the C Standard:

(C99, 6.10.1p4) "After all replacements due to macro expansion and the defined unary operator have been performed, all remaining identifiers (including those lexically identical to keywords) are replaced with the pp-number 0""