Finding Relocatable Modules

The linker is given the name of one or more program modules that should be included. These form the initial module set.

    cc driver.c graph1.s -lm

1. For each module, the exported symbols and imported symbols are collected.

2. If there is some imported symbol that is not defined, it is necessary to find a relocatable module that defines it. This is done by searching through one or more libraries, which are collections of relocatable files. This process typically occurs for system library routines such as sin or writeln.

3. The above processes are repeated until no undefined symbols remain. If a symbol cannot be found, an unsatisfied external reference error is reported.

4. If any external symbol is defined more than once, a multiply defined external symbol error is reported.