Resource file

A resource file is available to an application at run-time, and usually has extension .rsc. It contains resources compiled from a source file, .rss.

Each resource is a sequence of bytes. Resources within a file are identified by number at run-time, but may also be identified symbolically in the source file. The resource compiler rcomp compiles a .rss into a .rsc, and also emits a series of #define statements into a .rsg file, which the C++ program may #include, to allow resources lookup by symbolic name rather than by number.

Resources are built automatically by abld or the compiler IDE if the project file specifies a resource file using the RESOURCE statement.

Resource data is mapped by structs — in a similar way to C’s structs. Resource structs are defined using STRUCT statements which are understood only by the resource compiler. Symbian OS provides many struct types: occasionally, applications also add their own. STRUCT statements are included in headers, conventionally with a .rh extension. These are #included into .rss files.

Symbolic constants for various purposes must be available to both C++ programs and resource file definitions. These are defined using #define statements or enum statements, and included in .hrh files. These may be #included into either C++ or resource scripts.