 Linking (computing)

Linking combines separately produced program components and resolves references between them. A linker (computing) reads object files and library archives, assigns or adjusts locations through relocation (computing), and connects references to their definitions. GNU ld describes these as its central operations.^[ref]

For example, one object file contains a call to a procedure defined in a second object file. The first compiler invocation can leave a symbolic reference; linking supplies the connection once both components are available. A missing definition or conflicting definitions can cause an error even when both source files compiled separately. Depending on the toolchain, some connections are completed before execution and others when a shared software library is loaded.