Hacker News Reader

Comment by bjourne | Hacker News Reader

Why stick with c89? Can't think of any compilers that doesn't support c99 nowadays. The major benefit is that you can use uint8_t and friends directly and don't need to define your own wrapper types.

View on HN

It's more of a fun exercise, I guess. But I do have experience with at least one compiler that doesn't support C99: Zilog's ez80 C compiler. Back in the day I used to program my TI-84+ CE for fun[0], and the only C solution was a pretty bespoke C89-only compiler[1] distributed with a community toolchain[2], which has since switched to clang. It's somewhat irrational, but in the back of my mind it bugs me if the software I write can't run on platforms like that.

[0] https://github.com/mnurzia/chip8-ce

[1] http://www.zilog.com/docs/appnotes/pb0098.pdf

[2] https://ce-programming.github.io/toolchain/

One "advantage" (if one wants to call that) is that the code would also compile as C++, while C99 has diverged enough from the common C/C++ subset that one cannot use all C99 features in C++ mode.

I totally missed this, good point.

Slightly unrelated, but just thought I should mention: the sokol libraries are awesome!

There never was a "common C/C++ subset". See https://softwareengineering.stackexchange.com/a/298667/18260

Ah that old thing again ;)

C isn't a subset of C++ (and never was). But there's still a common subset of both the C and C++ languages which compiles both in a C compiler and a C++ compiler (and behaves the same at runtime despite slightly different C vs C++ semantics), and that common subset is what I call C/C++: the pidgin dialect that's neither quite C nor quite C++ but compiles as both.

I've met several people that seriously think that C89 is the peak of programming languages and that C99 just brings misfeatures (like, allowing variable declarations in middle of basic blocks according to them)

Forcing declares at the top makes it easy to estimate at a glance (or exactly calculate) how much space the stack frame will use.

Maybe in the early days of C, but with modern compilers doing stuff like keeping variables in only registers, inlining functions, stack cookies, merging non overlapping variables etc. that seems not really worth it. If you want to avoid accidental huge stack usage you can pass flag to gcc/clang to trigger warning when stack usage of a function goes over the specified limit.

Funnily enough, the file rv.h does use stdint.h if available and contains the following comment:

> All I want for Christmas is C89 with stdint.h

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-...

Reply on news.ycombinator.com