这个 C++ 语法是什么（模板&lt;&gt; struct __nv_tex_rmnf_ret<char> {typedef 浮点类型;}; ) 声明是什么意思？</char>

Question

In the CUDA header file, /usr/local/cuda/targets/x86_64/linux/include/texture_fetch_function.h , there is the following statements:

template<typename T> struct __nv_tex_rmnf_ret{};
template<> struct __nv_tex_rmnf_ret<char> {typedef float type;};

I understand the first statement is the definition of struct template. But what does the latter mean? I have never seen such C++ syntax before. Could anyony explain it? Thanks in advance.

Answer 1

template<> introduces an explicit specialization of a previously declared (primary) template (here the first line). It has otherwise the same syntax as the primary template uses, except that the name in the declarator (here __nv_tex_rmnf_ret ) is replaced by a template-id (here __nv_tex_rmnf_ret<char> ) which should be valid for the primary template.

Basically it replaces the definition of the template for the specific specialization determined by the template-id.

__nv_tex_rmnf_ret<char> is now a class containing a typedef for type , but all other specializations __nv_tex_rmnf_ret<T> where T is not char are completely empty classes.

Answer 2

It's called template specialization.

Edit: Removed low-quality link.