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In today's #TuesdayCodingTips, let's talk about an "explicit template instantiation" with tip 6.

Templated code in C++ must be defined in the header files (or a function within the same cpp file). This is because whenever a templated function is called, the compiler generates a new implementation using the concrete type the function was called with. If you split the definition from the declaration, you need to tell it what implementations to generate and link.

That's what explicit template instantiation is for. It is useful when you're writing generic code for a well-known subset of types, like string manipulation. It cannot be used for totally generic types because you need to be able to list all types the template will be used with (otherwise the user will get a linker error).