Funny if only marginally related fact: even though neither the C++11 syntax
if (int x = foo(); x) { ... }
if (int x = foo()) { ... }
int c99() {
enum { C99 = 1 };
{
if (sizeof(enum { C99 = 0 })) { }
return C99;
}
}
This is very cool, although a more compact way to check for single line comments (introduced in C99) versus division using "//* */". I used that trick here:
https://github.com/ioccc-src/winner/blob/a1c86c8a7a533e3c2cd...
You gave an IOCCC snippet as an example of a C99 coding trick you know? I mean, the code looks visually cool, but it's funny to explain a code concept using code shaped like an anime character. (At least that's what I think it is.)
I don't know how to link to just a specific part of the line, but the interesting bit is at the end of line 16 and the start of line 17:
With C89, this is evaluated as "x *= 02 / 2 - 1", or "x *= 0".With C99, this is evaluated as "x *= 02 / -1", or "x *= -2".
> I make no promises about the behaviour of this code on insufficiently anal compilers like TCC.
But tcc isn't a C++ compiler at all?
tcc version 0.9.28rc returns "1", whatever that means.
Pretty sure that means that tcc at least believes it is a C99 (or later) compiler; if it conformed to an earlier spec it (probably?) would have considered the inner `enum { C99 = 0 }` definition to be still in scope, and the return value would be 0.
I think.
That’s correct. I did check before posting that TCC 0.9.27 on Godbolt returned zero here, but I didn’t look beyond that. Evidently things have changed since that release.