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

[TestRealTime .]

Hello Florian,

I tried to check your assumption. I prepared a small code snipper which is compiled successfully. I think, it may be considered as some "evidence".

address@hidden:base> cat simple.c
int main()
{
    int x = 3;
    __typeof__(x) y = 4;
    long z;
    z = (__typeof__(z)) (x + y);

    char * s, * p;
    p = (__typeof__(s))malloc(10);
    return 0;
}

address@hidden:base> cc_r -o simple.o -c simple.c; echo $?
0
address@hidden:base> cc_r -o simple.o -q64 -c simple.c; echo $?
0
address@hidden:base> cc_r -qversion
C for AIX version 6.0.0.0

So, it looks like compiler understands the usage of __typeof__ in two use cases: a) as a type cast, b) as a type in the variable declaration.

So far I incline to think that it is a problem of compiler itself, what do you think?

--

Best Regards,

Alexander.

2016-10-31 10:05 GMT+01:00 Florian Weimer <address@hidden>:

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