变量模板和类型推导的模板特化 [英] Template specialization of variable template and type deduction

问题描述

template <class C>
C fnc();

template <>
int fnc(){return 0;}

template <class C>
C var;

template <>
int var = 0; // compile error

int main()
{
}

有一个 fnc 函数的特化声明，没有明确的类型指示(例如 int fnc())，所以推导出模板参数的类型从函数返回类型，但那东西对变量模板不起作用(它会导致编译器错误).这是所有已测试编译器(clang、gcc)中的正确行为还是错误?

There's a specialization of a fnc function declared without an explicit type indication (such as int fnc<int>()), so the type of template argument is deduced from the function return type, but that thing does not work for variable templates (it leads to compiler error). Is this a correct behavior or a bug in all compilers a have tested (clang, gcc)?

推荐答案

模板参数只能在函数模板的显式特化中省略.由于你有一个模板变量，你必须添加 部分:

Template arguments can only be omitted in explicit specialization of function templates. Since you have a template variable, you have to add the <int> part:

template <>
int var<int> = 0;

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