More C++ Idioms/Enable if
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Intent
[edit | edit source]Sometimes a member function of a class template (possibly one of an overloaded set) only makes sense for certain template parameters. The enable_if idiom uses SFINAE to eliminate unwanted functions before overload resolution.
Also Known As
[edit | edit source]Motivation
[edit | edit source]Solution and Sample Code
[edit | edit source]Known Uses
[edit | edit source]One use of enable_if is in implementing requirements such as that on the (size_type, value_type) constructor of a standard container, which has special behavior if the value_type is an integral type. More primitive solutions exist, but enable_if is elegant in this context.
Related Idioms
[edit | edit source]SFINAE, metafunctions.