What does a type followed by _t (underscore-t) represent?

Question

This seems like a simple question, but I can\'t find it with the Stack Overflow search or Google. What does a type followed by a _t mean? Such as

Answer 1

It is a standard naming convention for data types, usually defined by typedefs. A lot of C code that deals with hardware registers uses C99-defined standard names for signed and unsigned fixed-size data types. As a convention, these names are in a standard header file (stdint.h), and end with _t.