RC (Resource Compiler) is a tool that lets you add application resources, such as message strings, pointers, menus, and dialog boxes, to your application's executable file. The primary purpose of RC is to prepare data for applications that use functions such as WinLoadString, WinLoadPointer, WinLoadMenu, and WinLoadDlg. These functions load resources from the application's executable file or another specified executable file. The application then can use the loaded resources as needed.

RC and the resource functions let you define and modify application resources without recompiling the application itself. RC can modify the resources in an executable file at any time without affecting the rest of the file. You can create custom applications from a single executable file by using RC to add the custom resources you need to each application. RC is especially important for international language support because it lets you define all language-dependent data, such as message strings, as resources. Preparing the application for a new language is simply a matter of adding new resources to the existing executable file.