Re: Proposal: Add more compile-time asserts to expose inconsistencies.

On 2019-10-10 00:52, Smith, Peter wrote:
> I liked your idea of using an extern function declaration for implementing the file-scope compile-time asserts. AFAIK it is valid standard C.
> 
> Thank you for the useful link to that compiler explorer. I tried many scenarios of the new StaticAssertDecl and all seemed to work ok.
> https://godbolt.org/z/fDrmXi
> 
> The patch has been updated accordingly. All assertions identified in the original post are now adjacent the global variables they are asserting. 
> 

The problem with this implementation is that you get a crappy error
message when the assertion fails, namely something like:

../../../../src/include/c.h:862:84: error: size of array
'static_assert_failure' is negative

Ideally, the implementation should end up calling _Static_assert()
somehow, so that we get the compiler's native error message.

We could do a configure check for whether _Static_assert() works at file
scope.  I don't know what the support for that is, but it seems to work
in gcc and clang.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services