#elsif

[Ulrich Drepper]

eggert@twinsun.com (Paul Eggert) writes:

> As I read the C standard, if A is not defined, then GCC is required to
> accept that program fragment, though I admit the standard's wording is
> not entirely clear.

The wording may not, but section 6.8 is very clear.  `control line'
mentions only a fixed amount of possibilities which start with # and
which are handled separately.  All other input is handled as
preprocessing-token and is in case of a not fulfilled #if condition to
be ignored.  The current behaviour is therefore ok.

This also means that #elsif never must be an error but warnings can be
issued if one wants.  But since some compiler manufacturers invent new
# directives it is questionable.  (Of course # directives shouldn't be
introduced but this is something different).

I therefore vote against changing the current behaviour or at least
make the warning not available in -Wall.

-- Uli
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Ulrich Drepper  \    ,-------------------'   \  Sunnyvale, CA 94089 USA
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