Support both stateful and state-free asserts in one program

[jwdevel]

Currently, one must decide at compile time whether PPK_ASSERT will use a static bool _ignore flag or not (see: PPK_ASSERT_DISABLE_IGNORE_LINE).

However, I have a program that largely should use that bool, but can't in certain places.
The place where it is not allowed is inside a constexpr function.

eg:

constexpr int myFunc(int arg) {
    PPK_ASSERT(arg != 0);
    /* ... */
    return arg+5;
}

This fails to compile for me, with:

ppk_assert.h line 243 col 23: error: ‘_ignore’ declared ‘static’ in ‘constexpr’ function

So, it would be nice if there were some PPK_ASSERT_NOSTATE(...) set of macros that could be used in this case, even if the normal PPK_ASSERT(...) macros do keep state.

[gpakosz]

Hello @jwdevel 👋

I don't understand how this would fly 🤔

Even though you manage to use PPK_ASSERT in a constexpr function, I don't get how this composes with the fact that the handling part is designed to happen at runtime 🤷‍♂️

[jwdevel]

Hi @gpakosz,

Yes, I take your point, and maybe PPK_ASSERT is just a runtime-only facility.

I went down this path because I can use plain assert() in my constexpr functions. Having done some research, this is a C++14-specific thing. Even though it is constexpr, it will fail at runtime when the condition is met (at least, I just tried this on GCC 8.3).

So, maybe this request is a bit outside the scope of PPK_ASSERT.
I just thought it would be nice to take advantage of all the other machinery that PPK_ASSERT provides, handling various arguments, etc. But if it all boiled down to plain assert it could be used in a constexpr function on C++14.

In researching this, I found some interesting info, eg SO question, blog post.

So I guess feel free to close this if you like (: