#Practical examples to use 'extern constexpr bool' from CMake?

22 messages · Page 1 of 1 (latest)

sacred magnet
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I'd like to write assert in C++23 with CMake and multiple build modes as mentioned in https://learnmoderncpp.com/2020/02/10/writing-assert-in-cpp/ to use modules, meaning without preprocessor.
Do you have practical examples for that? Searching for "C++ extern constexpr" turned up no meaningful results.

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Writing assert() in C++

So we all know assert() from C’s Standard Library, right? If we implemented it ourselves as a macro, it might look something like this: #define assert(x, msg) \ if(!(x)) { fprintf(stderr, &#8…

chilly nimbusBOT
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fading igloo
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if you want to pass information from cmake to your code, defining macros is still the most straightforward way

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you can still do that with modules

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the only other way I could think of is using cmake to generate the source code defining your ReleaseBuild constants or whatever

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yes, you could do that, but why would you

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and with modules, you can keep them private

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nobody will be exposed to the macros just because they import your assert stuff

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sorta 😛

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sometimes 😛

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https://www.kitware.com/import-std-in-cmake-3-30/

import std in CMake 3.30

Since C++ named modules left the experimental state in CMake (see import CMake; the Experiment is Over!), CMake development has continued to add more support for modules. The most recent development is the experimental support of import std;. C++23 introduced support for APIs to be available via the named module std. This means that import […]

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still experimental support in cmake, only works on some compiler + stdlib + os combos

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maybe @sacred magnet likes living on the bleeding edge

sacred magnet
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I'd expect apps or libs to offer a reasonable named default module for configuring hardening etc.
However, I guess you are saying that because there is so far no standard cli for reproducing module interaction,
so using macros is simpler?!

fading igloo
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"reasonably named default module"?
"reproducing module interaction"??

sacred magnet
fading igloo
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when there are easier ways to affect the compilation... using compiler flags

sacred magnet
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ok, agreed.

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!solved

chilly nimbusBOT
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fading igloo