Matti Linsu <matti.linsu@xxxxxxxxx> writes: >> There is a space after 0_start_with_a_number because gcc emits a space >> whenever necessary to prevent tokens from accidentally pasting together. >> E.g., a space is required between '+' and '=' in preprocessor output. >> The test for whether a space is necessary is conservative. >> 0_start_with_a_number is not an identifier, so the conservative test >> says that a space is required. > > Could you give an example where tokens would accidentally be pasted together? > I cannot find any case where it would happen. I implied an example. Here it is in more detail: #define P() + #define E() = P()E() The preprocessor must insert a space between the '+' and the '=', otherwise it will produce the single token '+='. On the other hand: #define A() & P()A() The preprocessor does not have to preserve that space, because '+&' is always two tokens, and indeed gcc's preprocessor does not preserve it. Ian
