Putting code with side effects into an assert is asking for trouble. Compile with NDEBUG set and the effects mysteriously disappear! Anything beyond an equality expression or straight boolean should be avoided.
I once spent several days debugging that same mistake. Stuff worked perfectly in tests but broke misteriously in production builds. Couldn't stop laughing for a few minutes when I finally figured it out.
This is just a symptom of a bad assert() implementation, which funny enough is the standard. If you properly (void) it out, side effects are maintained.
assert() is meant to be compiled away if NDEBUG is defined, otherwise it shouldn't be called assert(). Given that assert() may be compiled away, it makes sense not to give it anything that has side effects.
Abseil has the convention where instead of assert(), users call "CHECK" for checks that are guaranteed to happen at run time, or "DCHECK" for checks that will be compiled away when NDEBUG is defined.
In C++ you should probably #include <cstdio> instead of <stdio.h> unless you have a good reason. And especially avoid #including both. <cstdio> provides the function std::getc(..) while <stdio.h> usually provides getc(..) as a macro.
htons(..) and related socket-utility names are also often macros, but I'm pretty sure there is not a std::htons(..) in the C++ standard, partly because 'htons' is not an attractive name. Since it's (sometimes) a macro don't qualify its namespace like ::htons(..).
A long time ago in the Microsoft C (and later C++) dev envs there were macros named "min" and "max", which I thought were terrible names for macros.
Yeah, but the macro system being so pitiful makes me long for one that allows something as magical as fiveam's is (https://github.com/lispci/fiveam/blob/e43d6c8e7da5a80d5c33e8...) instead of having to write special cases for unary and binary predicates.
Preprocessor is just doing text transformations on the sources.
It's not really something that can be fixed, other than moving away from the preprocessor and putting metaprogramming capabilities into the language itself (which C++ has been doing).
https://github.com/fiberfs/fiberfs/blob/7e79eaabbb180b0f1a79...
Abseil has the convention where instead of assert(), users call "CHECK" for checks that are guaranteed to happen at run time, or "DCHECK" for checks that will be compiled away when NDEBUG is defined.
https://github.com/abseil/abseil-cpp/blob/0093ac6cac892086a6...
https://github.com/abseil/abseil-cpp/blob/0093ac6cac892086a6...
`assert(vector.size() < 3)` is ridiculous to you?
But your meaning is clear. In an assert expression, don't call functions that might change the program/database state. Be as "const" as possible.
There are a few things like that, for example:
https://en.cppreference.com/w/c/numeric/math/isnan - isnan is an implementation defined macro.
https://en.cppreference.com/w/c/io/fgetc - `getc` may be implemented as a macro, but often it's a function.
htons(..) and related socket-utility names are also often macros, but I'm pretty sure there is not a std::htons(..) in the C++ standard, partly because 'htons' is not an attractive name. Since it's (sometimes) a macro don't qualify its namespace like ::htons(..).
A long time ago in the Microsoft C (and later C++) dev envs there were macros named "min" and "max", which I thought were terrible names for macros.
https://github.com/fiberfs/fiberfs/blob/7e79eaabbb180b0f1a79...
In this case, the ability to see the actual values that triggered the assert is way more helpful.
It's not really something that can be fixed, other than moving away from the preprocessor and putting metaprogramming capabilities into the language itself (which C++ has been doing).