Re: __typeof__ does not work as expected with XLC compiler on AIX 5.2

[Florian Weimer]

On 10/28/2016 05:13 PM, TestRealTime . wrote:
> Hello,
>
> I would like to report about two (probably, self-connected) bugs in the
> __typeof__ C function.
> These bugs are reproduced when I am trying to compile a simple code with
> XLC compiler on AIX 5.2. Please, look at the code snippets below.
>
> 1. typeof_example_1.c
> long Func(int x) { return x; }
> int main()
> {
>     int y, z = 1;
>     y = (__typeof__(Func(z)))0;
>     return 0;
> }
>
> cc_r typeof_example_1.c
> "typeof_example_1.c", line 5.26: 1506-045 (S) Undeclared identifier z.
>
> The 'z' variable is obviously defined, so "Undeclared identifier" message
> is wrong.

Do you have any evidence that the compiler supports __typeof__ at all? 
Maybe the compiler treats __typeof__ as an implicitly declared function.

> What is interesting, we use cc_r, but not xlc binary in our build system
> (it is probably due to historical reasons and persons who can answer me why
> exactly cc_r have gone many years ago). But with xlc both code snippets
> also fail, however with other error messages (no matter, 32 or 64bit).
> xlc typeof_example_1.c
> "typeof_example_1.c", line 5.30: 1506-275 (S) Unexpected text integer
> constant encountered.
> xlc typeof_example_2.c
> "typeof_example_2.c", line 5.41: 1506-275 (S) Unexpected text z encountered.
> "typeof_example_2.c", line 5.45: 1506-275 (S) Unexpected text integer
> constant encountered.

Those syntax errors are consistent with not supporting __typeof__ at 
all.  The expression parts which contain __typeof__ are not recognized 
as types, and so the expression is not recognized as a cast.

Florian