Re: [boost] Does boost have an assert that works nicely with constexpr evaluation, and if not should we add one?

David P. Riedel wrote:

On 8/21/21 11:54 AM, Peter Dimov via Boost wrote:

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Ivan Matek wrote:

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As you may know assert does not play nicely with constexpr evaluation.

It does. https://www.godbolt.org/z/KhPja6cEs

What am I missing here?

I click the above link and see the code

If I compile with gcc x86-64 trunk, I get the following:

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source>: In function 'int main()': <source>:12:21: error: non-constant condition for static assertion 12 | static_assert(5 == func(9,1)); | ~~^~~~~~~~~~~~ In file included from /opt/compiler-explorer/gcc-trunk- 20210825/include/c++/12.0.0/cassert:44, from <source>:2: <source>:12:28: in 'constexpr' expansion of 'func(9, 1)' <source>:6:5: error: call to non-'constexpr' function 'void __assert_fail(const char*, const char*, unsigned int, const char*)' 6 | assert(a

That's because the assertion fails. a=9, b=1.