Why Can't C Function Templates Be Partially Specialized?

Why Partial Specialization of Function Templates is Forbidden in C

Function templates in C cannot be partially specialized. This has often been considered a limitation, as partial specialization can provide a more convenient and concise way to handle specific scenarios. However, there are reasons why this feature is not supported.

Rationale

The lack of partial specialization for function templates was likely an oversight in the initial design of the language. As noted in the provided answer, it is possible to achieve a similar effect by using static member functions within classes.

However, it's important to note that partial specialization for function templates would introduce certain complexities. One concern is that it could lead to ambiguity in overload resolution, as it would allow multiple partially specialized functions to match a particular function call. Another potential issue is that it could make it more difficult for compilers to optimize code, as they would have to consider a wider range of possible template instantiations.

Alternatives and Workarounds

While partial specialization of function templates is not available, there are alternatives that can provide similar functionality. One option is to use ADL (argument-dependent lookup) to select an appropriate function template based on the types of its arguments. Another approach is to use template metaprogramming techniques to generate specialized code at compile time.

Further Research

It's worth noting that there have been ongoing discussions within the C community about potentially introducing partial specialization for function templates in future versions of the language. However, as the provided answer indicates, there is no evidence of this being supported in the current C 0x draft standard.

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