How can I use string literals as non-type template arguments in C ?

Passing String Literals as Non-Type Template Arguments

In the realm of C templating, declaring a class template that accepts a string literal as a non-type template parameter can be a perplexing task. Many programmers desire the ability to specify a string literal directly in a template declaration, such as my_class<"string">.

To address this need, while C does not directly allow passing string literals as non-type arguments, a solution utilizing const character arrays can be employed. By defining a statically linked const char[] variable and passing it as the template parameter, we achieve a similar effect to using string literals.

Here's a compilable code snippet that demonstrates this approach:

#include <iostream>

template<const char *str>
struct cts {
    void p() {std::cout << str;}
};

static const char teststr[] = "Hello world!";
int main() {
    cts<teststr> o;
    o.p();
}

In this example, a statically linked const char[] variable named teststr is defined with the value "Hello world!". By passing teststr as the non-type template parameter to the cts class template, we effectively achieve the desired behavior of using a string literal.

Running this code produces the following output:

Hello world!

This technique provides a workaround to the lack of direct support for passing string literals as non-type template arguments in C , allowing programmers to define class templates that accept string-like values in a convenient manner.

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