Microsoft Windows std.stdio.File.lock(), tryLock(), unlock(): do not allocate memory for error messages when they are not needed

[n8sh]

No description provided.

[dlang-bot]

Thanks for your pull request, @n8sh!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	21523	enhancement	Microsoft Windows std.stdio.File.lock(), tryLock(), unlock(): do not allocate memory for error messages when they are not needed

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#7740"

[CyberShadow]

Why not just make the wenforce argument lazy?

[n8sh]

Because I wanted to be able to add pragma(inline, false) and have it only affect the cold path. In your opinion was the other way better?

[CyberShadow]

From a code readability standpoint, enforce variants are better than explicit if constructs. if being a control flow structure should be used for important aspects of the function's algorithm, but when it's used for trivial error handling, it becomes a distraction.

lazy would put the code constructing the error message string into its own function (implicit lambda), so that should achieve something similar, right?

In any case, optimizing without benchmarking is usually not practical, and optimizing CPU for functions doing I/O is usually not very impactful.

Edit: FWIW, std.exception.enforce has its message argument as lazy, so going that way would be consistent with it.

[n8sh]

I have made the suggested change.

[CyberShadow]

Thanks!