Paul Eggert wrote: > >> (I would not bet that code like this: > >> #if 0 > >> # if @FOOBAR@ > >> # endif > >> #endif > >> works for all C and C++ compilers. Better avoid that.) > > I always wondered if a compiler would fail with that. > > The C standard has required it to work ever since C89 (see its section > 3.8.1), and I don't know of any compiler where it does not work.
Thanks for explaining. In ISO C 23 it's ยง 6.10.2.(17); same wording. But anyway, writing # if defined __GL_FOOBAR__ instead of # if @FOOBAR@ is correct. We used @FOOBAR@ to make it _look_ like an AC_SUBST substitution. Bruno
