Can C-Style Strings Be Template Arguments in C ?

C-Style Strings as Template Arguments

In the realm of C programming, you may have encountered a dilemma: attempting to employ C-style strings as template arguments. This article delves into the issue and a potential workaround.

The following code snippet illustrates the attempt:

<code class="cpp">template <char *str>
struct X {
    const char *GetString() const {
        return str;
    }
};

int main() {
    X<"String"> x;
    cout << x.GetString();
}

However, despite the lack of compilation errors in the class definition, the instantiation yields an error message. The issue lies in the attempt to use a string literal as a template argument, which is not supported by the compiler.

A simple solution involves replacing the string literal with a character pointer:

<code class="cpp">char global_string[] = "String";

template <char const *str>
struct X {
    const char *GetString() const {
        return str;
    }
};

int main() {
    X<global_string> x;
    cout << x.GetString();
}</code>

This code will successfully compile and execute, allowing you to retrieve the stored string using the GetString method.

Note that with the advent of C 11, it is now possible to employ string literals as template arguments using character packs. However, for compilers supporting earlier C versions, the workaround presented here remains a viable option.

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