[GermanAizek]

@jpeisach

Fix common C/C++ compiler flaw is that it doesn't optimize strlen calls inside loops.

Reference:

• https://stackoverflow.com/questions/78827988/why-doesnt-the-compiler-optimize-strlen-calls-in-a-loop-despite-it-being-a-p

Since I started contributing to heavily optimized AV1 decoder (ffmpeg dav1d), there are high performance requirements. I experimentally found out that putting calculated expressions from the body of the loop into separate constants gives a strong two-fold increase. What is strange is the C/C++ compiler that GCC and Clang on -O3 cannot automatically optimize.

It's also visually more readable with a separate const variable.

• https://code.videolan.org/videolan/dav1d/-/merge_requests/1896
• https://code.videolan.org/videolan/dav1d/-/merge_requests/1897
• https://code.videolan.org/videolan/dav1d/-/merge_requests/1898
• https://code.videolan.org/videolan/dav1d/-/merge_requests/1903

[jpeisach]

I don't see any harm doing this - we don't want to compute strlen multiple times anyway

[tintou]

Here we were doing strlen of constant expression, there shouldn't be any difference, the example you're linking is not the same as this, the only real occurrence is at src/session.c

[jpeisach]

it's still a constant calculated expression. Also I imagine on builds with no compiler optimization at all, this would prevent the call from being made each time there is a .desktop file.