Common Errors with Function Templates

When working with function templates, you may encounter some common compile-time errors:

1. Undefined template arguments: If the compiler is unable to deduce the template arguments and you haven't provided them explicitly, you'll get an error. Make sure to provide the necessary template arguments or ensure the function arguments allow template argument deduction.
2. Type mismatch: If the types of the function arguments don't match the types expected by the function template, you'll get a compilation error. Double-check that the types align or use explicit casts if needed.
3. Ambiguous overloads: If there are multiple function template overloads that match the provided arguments, the compiler may report an ambiguity. To resolve this, you can use explicit template arguments to specify which overload to use.

Example of an ambiguous overload:

1template <typename T>
2void foo(T a, T b) {/* ... */ }
3
4template <typename T>
5void foo(T a, int b) {/* ... */ }
6
7int main() {
8  foo(1, 2);// Ambiguous: both foo<int>(int, int) and foo<int>(int, int) match
9}

To fix the ambiguity, explicitly specify the template arguments:

1codefoo<int>(1, 2);// Uses foo<T>(T, T)