Question

I am using templates for my struct like:

#pragma pack(push, 1)
template <typename T>
struct S
{
   T t;

   inline void Set(const T& val) { t = val; }
}
#pragma pack(pop)

T can be an float, int, short or char[10], char[1] or char[2] (and preferably any length would be great).

While the above seems to work quite nicely for the integral types, I’m having difficulty implementing the char[n] portion in that:

1. I need to use strncpy or memcpy instead of the assignment operator
2. Using the above, the compiler complains about the signature (const char[2]& val) and my calling it via s.Set(“T”).
3. The interface between S with integral and character types has to be same as it’s generic code that is calling them (and it doesn’t care what type they are).

Answer 1

You can define template specializations for T in the case of char[10], etc. Do any issues remain when you do that? But as Mat has already noted, using a string is an approach worth considering.

#include <iostream>

#pragma pack(push, 1)
template <typename T>
struct S
{
   T t;

   inline void Set(const T& val) { std::cout << "general\n"; }
};

template <int len>
struct S<char[len]>
{
   char t[len];

   inline void Set(const std::string& val) { std::cout << "specialization\n"; }
};
#pragma pack(pop)

int main() {

    S<int> a;
    a.Set(10);

    S<char[20]> b;
    b.Set("turkey!");

    return 0;
}

http://codepad.org/X8YVuFja output:

general
specialization