 For example, a program such as Firefox, which already runs on Windows on the x86 family, can be modified and re-built to run on Linux on the x86 (and potentially other architectures) as well.The multiple versions of the code may be stored as separate codebases, or merged into one codebase by conditional compilation (see above).Note that, while
porting must be accompanied by cross-platform building, the reverse is not the case.