Pre-defined Macros

The preprocessor has a number of pre-defined macros. All have names starting and ending with two underscores (__). To avoid conflicts, user-defined macros should not use this naming convention.

Pre-defined macros are either built-in, or they are set by the #pragma, General Purpose directive, as indicated in the table below.

Name	Type	Set by	Description
__AVRASM_VERSION__	Integer	Built-in	Assembler version, encoded as (1000*major + minor)
__CORE_VERSION__	String	#pragma, General Purpose	AVR core version
__DATE__	String	built-in	Build date. Format: "Jun 28 2004". See AVR Assembler Command Line Options
__TIME__	String	built-in	Build time. Format: "HH:MM:SS". See AVR Assembler Command Line Options
__CENTURY__	Integer	built-in	Build time century (typically 20)
__YEAR__	Integer	built-in	Build time year, less century (0-99)
__MONTH__	Integer	built-in	Build time month (1-12)
__DAY__	Integer	built-in	Build time day (1-31)
__HOUR__	Integer	built-in	Build time hour (0-23)
__MINUTE__	Integer	built-in	Build time minute (0-59)
__SECOND__	Integer	built-in	Build time second (0-59)
__FILE__	String	built-in	Source file name
__LINE__	Integer	built-in	Current line number in source file
__PART_NAME__	String	#pragma, General Purpose	AVR part name
__partname__	Integer	#pragma, General Purpose	partname corresponds to the value of __PART_NAME__. Example: #ifdef __ATmega8__
__CORE_coreversion__	Integer	#pragma, General Purpose	coreversion corresponds to the value of __CORE_VERSION__. Example: #ifdef __CORE_V2__