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Comment by contrarian1234 | Hacker News Reader

Did Visual Studio finally make the jump?! (you could always just compile it as C++ code though)

Nope stdint.h has been in msvc for over 10 years. Other c99 features may be not supported though.

MSVC did a big rewrite of the C frontend around MSVC2013. I haven’t encountered C99 idioms that don’t work nowadays. Granted, I might not use every feature in my typical coding style…

It's been "fully" C99 (and C11, C17) compliant for about 2 or 3 years. The only missing C99 featured before that were relatively rarely used ones like _Pragma.

It's not C99 compliant because that would require VLA support (which has been made optional in C11, which in turn enabled MSVC to be a C11 and C17 compiler, but not C99. Not that it matters much in practice though :)

Hasn't the main issue with MS been VLAs? I seem to recall that VLAs are the main reason MSVC won't ever support C99, and that MSVC is one of the main reasons why VLAs were made optional. It seems like MSVC supports C11 and C17 now, thanks to the removal of mandatory VLAs.

vehement oppostion from ms my be one of the reasons for them being optional (and thus worthless) but the main one is that that they are impossible to use correctly. what happens if you make one too big?

I think they could potentially have some very limited valid use cases, but I agree that a fixed length array and/or heap allocation is usually much better than VLAs.

I was mainly just pointing out that MS's lack of C99 support isn't really a part of keeping C89 alive, especially now that they officially support C11.

I'm not sure how robust that support is though: https://discuss.python.org/t/requiring-compilers-c11-standar...

If the reply is correct, the only issue there is that they're compiling in C89 mode. If you pass `-pedantic -std=c89` to GCC, it too will warn on C99+ features. If you pass `/std:c11` or `/std:c17` to MSVC, C99+ features should work.

> what happens if you make one too big?

Doesn't that apply to fixed length arrays too?

It does, but if you create a fixed length array that's too big, you'll just deterministically blow the stack regardless of user input. With VLAs (or alloca), your array length is determined by some runtime property. Whether you blow the stack doesn't just depend on the code path any more, but on the data you're operating on too.

As a bonus, that data is often user input...

The whole security industry has vettoed VLAs.

Google even went the extra pay to pay the effort to remove them from the Linux kernel.

Yeah, that's my point. The situation isn't, "MS is garbage, they only support C89"; the situation is "MS supports modern C pretty well, their lack of official C99 supports is just a technicality caused by VLAs which you shouldn't use anyway".

Except for VLAs (which are optional post-C99 anyway), MSVC actually has pretty good support for recent C versions, and since 2020 they're basically back on the "modern C" train: https://devblogs.microsoft.com/cppblog/c11-and-c17-standard-...

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