Question

Recently, I tested some template code on Codepad. Althought the code is correct, GCC is giving me a really strange error. I also tested it on Ideone:

Tested code:

template<int num>
struct count;

template<>
struct count<-1>
{
};

int main()
{
 return 0;
}

Here are the results, on Codepad (GCC 4.1.2) and Ideone (GCC 4.3.4) : GCC 4.1.2 outputs:

Line 5: error: 'count' is not a template

while GCC 4.3.4 compiles normally without errors.
Is this really a compiler bug, or is my code not correct (and compile thanks to extensions?)

Answer 1

If I try

template<int num>
struct count;

template<>
struct count<-1>
{
};

int main()
{
 return 0;
}

with g++ 4.1.2, I don’t have a problem. If I try

#include <algorithm>
using namespace std;

template<int num>
struct count;

template<>
struct count<-1>
{
};

int main()
{
 return 0;
}

with g++ -Wfatal-errors I get

count.cpp:8: error: 'count' is not a template
compilation terminated due to -Wfatal-errors.

So my guess is that Codepad is forcing a preamble on you which triggers the error.