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Comment by jmgao | Hacker News Reader

A strlen of a compile-time constant, which will certainly get turned into a constant by the compiler. It does not get the length of the input string.

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Why wouldn't the string_view constructor be inlined and get the same treatment?

Certainly isn't a fact unless proven by examining the generated machine code.

This is a worthless statement. Do you examine all of your generated machine code to ensure that it generates correct code? Any compiler that you cannot trust to inline 3 for strlen("foo") is not one you should trust to compile anything, let alone modern C++.

> Do you examine all of your generated machine code to ensure that it generates correct code?

(not OP). I examine the output if someone tells me it's slower, or if I care about performance. I did a very rough benchmark which says in this case they're equivalent [0], however that's not necessarily representative of the places it's called in. There's definitely a compile time overhead though [1]. On my current project there's ~20k files. On an 8 core machine (as an example), adding 150ms per file would add 7 minutes onto a clean build (before optimising the builds).

[0] https://quick-bench.com/q/LBarCDIigwpmXcwZSx-RgV2x4_4 [1] https://build-bench.com/b/OH8qf9AgEB_l-BhANV5qP_uSCys

ISO C++ abstract machine and what a random C++ compiler generates out of it, don't require at any moment the realisation of your assertion.

So you either validate it actually takes place or believe in fairy tales.

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