Translation unit (programming)
（重定向自Compilation unit）
In C programming language terminology, a translation unit is the ultimate input to a C compiler from which an object file is generated. In casual usage it is sometimes referred to as a compilation unit. A translation unit roughly consists of a source file after it has been processed by the C preprocessor, meaning that header files listed in #include directives are literally included, sections of code within #ifdef may be included, and macros have been expanded.