Atmel CAVR-4 Manual De Usuario

CAVR-4

Descriptions of language extensions

Reference Guide

A translation unit (source file) is allowed to be empty, that is, it does not have to contain 
any declarations.

In strict ISO/ANSI mode, a warning is issued if the translation unit is empty.

The following source file is only used in a debug build. (In a debug build, the 

NDEBUG

 

preprocessor flag is undefined.) Since the entire contents of the file is conditionally 
compiled using the preprocessor, the translation unit will be empty when the application 
is compiled in release mode. Without this extension, this would be considered an error.

#ifndef NDEBUG

void PrintStatusToTerminal()

{

  /* Do something */

}

#endif

This extension, which makes it legal to place text after preprocessor directives, is 
enabled, unless strict ISO/ANSI mode is used. This language extension exists to support 
compilation of old legacy code; we do not recommend that you write new code in this 
fashion.

#ifdef FOO

  ... something ...

#endif FOO /* This is allowed but not recommended. */

The IAR Systems language extensions allow that you first declare the name of an 

enum

 

and later resolve it by specifying the brace-enclosed list.

It is allowed to place an extra comma at the end of an 

enum

 list. In strict ISO/ANSI 

mode, a warning is issued.