非常宽泛的字词：

• cuda.h 定义了CUDA
  驱动程序API的公共主机
  函数和类型。


• cuda_runtime_api.h 定义
  CUDA运行时API的public
  主机函数和类型


• cuda_runtime.h 定义 cuda_runtime_api.h 键入
  用于CUDA语言扩展和
  设备固有函数的定义和函数覆盖。

• cuda.h defines the public host functions and types for the CUDA driver API.
• cuda_runtime_api.h defines the public host functions and types for the CUDA runtime API
• cuda_runtime.h defines everything cuda_runtime_api.h does, as well as built-in type definitions and function overlays for the CUDA language extensions and device intrinsic functions.

主机代码要与包含API调用的主机编译器一起编译，您可以包括 cuda.h 或 cuda_runtime_api.h 。如果您需要其他CUDA语言内置函数（如类型），并且正在使用运行时API并使用主机编译器进行编译，则可以包括 cuda_runtime.h 。如果你编写的代码将使用nvcc编译，这一切都是无关紧要的，因为nvcc会自动处理所有需要的头文件，而无需程序员干预。

If you were writing host code to be compiled with the host compiler which includes API calls, you would include either cuda.h or cuda_runtime_api.h. If you needed other CUDA language built-ins, like types, and were using the runtime API and compiling with the host compiler, you would include cuda_runtime.h. If you are writing code which will be compiled using nvcc, it is all irrelevant, because nvcc takes care of inclusion of all the required headers automatically without programmer intervention.