[DougGwyn]

The main editing needed to bring "old C" source code up to snuff using a "modern C" compiler is to make sure that the standard header-defined types are used. No more assuming that a lot of things are, by default, int type. A second, related editing pass is to make sure all functions are declared as prototypes, no longer K&R style; K&R style is slated to be deprecated by the next version of the Standard. (There are some rare uses for non-prototyped functions, but evidently the committee thinks there is more benefit in forcing prototypes.)

[defectbydesign]

So the ISO committee breaks the backward compatibility of C in behalf of modernity... but there is C++ guys!

A little effort and you could make C deprecated. ;-)

This makes me think that there are as many C++ gurus than Go(ogle) gurus who want to kill C to be the new Java which brings you a bad coffee from a dirty kitchen.

[jart]

> but evidently the committee thinks there is more benefit in forcing prototypes

Why?

Consider the following code:

    LetsReconsiderPriorities(n, A)
      int n, A[n];
    {
      return A[n + 1];
    }

    main() {
      static int A[1];
      return LetsReconsiderPriorities(1, A);
    }

Can anyone guess what clang/gcc complain about? They complain about K&R syntax, yet say nothing about the buffer overflow error. Thanks to modern arrays, the overflow can be said to clearly contradict the intentions of the program author. So why aren't compiler authors focusing on that? Rather than showing warnings that I'd say rightfully belong in lint? Note: Same is true with -Wall, [static n], and even [static 1]: compiler complains about language style and ignores real bugs.

I would estimate that roughly 15% of the issues / pull requests that get filed against C language projects are due to these linter errors that accumulated in compilers over the years, based on a quick glance at STB. https://github.com/nothings/stb/issues?q=warning (29 + 132.) / (156 + 794) It's a big obstacle to sharing C code with others. It'd be great if the C Language Committee could ask compiler authors to remove all these distracting warnings like "unused parameter" now that we have amazing tools like runtime sanitizers that deliver real results.

Also, have we considered addressing the prototype problem with the freedom to choose an ILP64 data model instead? How much do prototypes honestly matter in that case? DSO ABI compatibility might be an issue for Linux distros, but it doesn't concern all of us. Also not terribly concerned about 64-bit type promo since 16-bit is usually what fast DSP wants, and the language today doesn't make that easy.

Lastly consider that C was designed at a research laboratory. If there's one thing researchers love to do, it's what I like to call "yolo coding" which is perfectly valid use case of getting experimental / prototyping code written in a way where one needn't care too much about language formalities and best practices. It'd be great if the standards committee acknowledged that as being a legitimate use case (similar to how "high level assembler" is explicitly acknowledged), because future revisions of the language should ideally maintain as much of the original intentions as possible. See also: https://www.lysator.liu.se/c/dmr-on-noalias.html (Note: I think dmr goes too far here, but interesting bit of history to think about, now that everything that isn't char is implicitly noalias!)

In other words, let us choose. Please don't force us.