Duncan Coutts authored 2 years ago and Marge Bot committed 11 months ago

We have lots of functions with conditional implementations for
different I/O managers. Some functions, for some I/O managers,
naturally have implementations that do nothing or barf. When only one
such I/O manager is enabled then the whole function implementation will
have an implementation that does nothing or barfs. This then results in
warnings from gcc that parameters are unused, or that the function
should be marked with attribute noreturn (since barf does not return).
The USED_IF_THREADS trick for fine-grained warning supression is fine
for just two cases, but an equivalent here would need
USED_IF_THE_ONLY_ENABLED_IOMGR_IS_X_OR_Y which would have combinitorial
blowup. So we take a coarse grained approach and simply disable these
two warnings for the whole file.

So we use a GCC pragma, with its handy push/pop support:

 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wsuggest-attribute=noreturn"
 #pragma GCC diagnostic ignored "-Wunused-parameter"

...

 #pragma GCC diagnostic pop