4. Differences to the ISO standard

Here is a list of differences between the language, the compiler accepts, and the one defined by the ISO standard:

• The compiler allows unnamed parameters in parameter lists. The compiler will not issue warnings about unused parameters that don't have a name. This feature can be disabled with the --standard command line option.
• The compiler has some additional keywords:
  • asm
  • __asm__
  • fastcall
  • __fastcall__
  • __AX__
  • __EAX__
  • __func__
  • __attribute__

  The keywords without the underlines can be disabled with the --standard command line option.

• The datatypes "float" and "double" are not available.
• The compiler does not support bit fields.
• C Functions may not return structs (or unions), and structs may not be passed as parameters by value. However, struct assignment *is* possible.
• Part of the C library is available only with fastcall calling conventions (see below). It means that you must not mix pointers to those functions with pointers to user-written, not-fastcall functions.

There may be some more minor differences I'm currently not aware of. The biggest problem is the missing float data type. With this limitation in mind, you should be able to write fairly portable code.