MS Visual C ++：您何时应该关注使用调用约定？

In C/C++ (specifically, I'm using MSVS), in what situation would one ever need to worry about specifying a calling convention for a function definition? Are they ever important? Isn't the complied capable of choosing the optimal convention when necessary (ie fastcall, etc).In C/C++ (specifically, I'm using MSVS), in wha