Generally speaking, keil doesn't have those type definitions. What if it is in a program compiled by someone else? Maybe he has his own type alias, or you don't have a header file containing the response. In fact, you can define it yourself, and it's not a very troublesome thing.

The advantage of this is that you don't need to write a long list of types every time, which simplifies one purpose of the program. This alias is also quite good. You can tell at a glance that it is 32-bit plastic surgery. As long as you know what its function is, it is easy to change and you don't need to be too entangled!