Translation unit (programming)

This article is about the C programming term. For the linguistic meaning of the term, see translation unit.

In C programming language terminology, a translation unit is the ultimate input to a C compiler from which an object file gets generated.

Context

A C program consists of units called source files (or preprocessing files). When the C preprocessor expands a source file with all header files declared by #include directives, the result is a preprocessing translation unit. Further preprocessing translates the preprocessing translation unit into a translation unit. From a translation unit, the compiler generates an object file, which can be further processed and linked (possibly with other object files) to form an executable program.