Re: AC_PROG_CC_C99

[Kevin P. Fleming]

Paul Eggert wrote:

> Part of the motivation for keeping that stuff hidden is that we don't
> want people to switch based on whether our macro "thinks" the compiler
> is "C99" or "C89" or "not".  They should switch based on the
> particular feature that they need.

Hmm... I see your point, but wouldn't that then mean that the macro 
would need to individually test for each C99 feature and store the 
results into variables for the configure script to check? Even using the 
variable you proposed earlier, the user would still only know "yes or 
no" for C99 support, unless I misunderstood.

Switching based on particular features they need sounds scary to me; in 
a project where there are multiple developers who have been told "our 
project demands C99 support from the build system", they will feel free 
to use C99 features wherever they want. This might not get communicated 
to the person in charge of configure.ac, and so the project could 
suddenly stop building on systems it used to build on because that 
compiler doesn't support all C99 features. This is a very hairy problem 
to solve, no doubt.