SFINAE (Substitution Failure Is Not An Error)

SFINAE (Substitution Failure Is Not An Error) is a C++ feature that allows the compiler to selectively enable or disable template instantiations based on whether certain types or expressions are valid. When the compiler tries to instantiate a template with specific types, if substitution leads to a compiler error, it simply ignores that template and searches for other matches instead. This mechanism enables developers to create flexible, type-safe code that adapts to different contexts, effectively managing multiple functions or classes that depend on specific type traits or capabilities without causing compilation errors.