[cfe-dev] C++11 POD bug

[Kal Conley]

Hi,

You are probably correct about that. But the compiler isn't complaining
about the VLA itself, only that the type is a non-POD. I think "Pod"
should be a POD type in c++11. Here is a more direct example:

$ cat pod.cc
#include <type_traits>
struct Pod {
  int i;
  Pod() = default;
};

static_assert(std::is_pod<Pod>::value, "Pod should be a POD");


$ ~/devel/llvm-install/bin/clang++ --std=c++11 --stdlib=libc++ pod.cc
pod.cc:7:1: error: static_assert failed "Pod should be a POD"
static_assert(std::is_pod<Pod>::value, "Pod should be a POD");
^             ~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

--Kal

Am 6/3/12 11:43 AM, schrieb Suman Kar:
> Your array size specifier is a non-const object making it a variable
> length array. VLAs are part of C99. They are not (yet) a part of
> standard C++. This thread may be of interest to you
> (<http://groups.google.com/group/comp.std.c++/browse_thread/thread/2bfe25800d4961e8/9545494bbb336dfa?pli=1>).
>
> However, you can always use a compile time constant to specify the
> size of the array.
>
> struct Pod {
>  int i;
>  Pod() = default;
> };
>
> int main(int argc, char **argv) {
>  const int Size = 1;                // compile time constant
>  struct Pod PodArray[Size];
>  return 0;
> }
>
> This compiles fine.
>
> Regards,
> Suman
>
> On Sun, Jun 3, 2012 at 4:00 AM, Kal Conley <kcconley at gmail.com> wrote:
>> Hi,
>>
>> I have the following code:
>>
>> $ cat pod.cc
>> struct Pod {
>>  int i;
>>  Pod() = default;
>> };
>>
>> int main(int argc, char **argv) {
>>  int Size = 1;
>>  Pod PodArray[Size];
>>  return 0;
>> }
>>
>> I believe that "Pod" should be a POD type in c++11. But when I try to
>> compile this with clang I get:
>>
>> $ clang++ --std=c++11 pod.cc
>> pod.cc:8:15: error: variable length array of non-POD element type 'Pod'
>>  Pod PodArray[Size];
>>              ^
>> 1 error generated.
>>
>> I'm using:
>>
>> $ clang++ --version
>> clang version 3.1 (trunk 156916)
>> Target: x86_64-apple-darwin11.4.0
>> Thread model: posix
>>
>> Thanks,
>> Kal
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