When you choose a target configuration, you implicitly choose a code format. If you use Real-Time Workshop Embedded Coder, for example, the code generated will be in embedded C format. The embedded C code format is a compact format designed for production code generation. Its small code size, use of static memory, and simple call structure make it optimal for embedded applications.
Many other targets, such as the generic real-time (GRT) target, use the real-time code format. This format, less compact but more flexible, is optimal for rapid prototyping applications.
And see the comparison chart, https://www.physiol.ox.ac.uk/Computing/Online_Documentation/Matlab/toolbox/rtw/rtw_ug/codefor3.html#1011734
