Can You Explicitly Specify Template Parameters in Constructors in C 03?

Explicit Template Parameter Specification in Constructors

Despite the ability for constructors to be template functions, the C 03 standard does not provide syntax to explicitly specify their template parameters. Instead, the compiler automatically determines these parameters based on the provided arguments.

Consider the following example:

struct A {
  template<typename T>
  A() {}
};

To instantiate this class, you cannot explicitly specify the template parameter. Instead, you must rely on the compiler to infer it from the arguments passed to the constructor:

A<int> a;  // Constructs an A object with template value int

The C 03 standard explicitly states:

[Note: because the explicit template argument list follows the function template name, and because conversion member function templates and constructor member function templates are called without using a function name, there is no way to provide an explicit template argument list for these function templates.] (§14.5.2/5)

This limitation may hinder debugging efforts if the compiler fails to determine the correct template parameters. Explicit parameter specification could enhance error messages and potentially resolve the issue. However, it is not supported by the C 03 standard.

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