=====Predefined preprocessor variables=====

Syntax:
<code>
    __LINE__
    __FILE__
    __DATE__
    __TIME__
    __cplusplus
    __STDC__
</code>

The following variables can vary by compiler, but generally work:

  * The ''%%__LINE__%%'' and ''%%__FILE__%%'' variables represent the current line and current file being processed.
  * The ''%%__DATE__%%'' variable contains the current date, in the form month/day/year. This is the date that the file was compiled, not necessarily the current date.
  * The ''%%__TIME__%%'' variable represents the current time, in the form hour:minute:second. This is the time that the file was compiled, not necessarily the current time.
  * The ''%%__cplusplus%%'' variable is only defined when compiling a C++ program. In some older compilers, this is also called ''c_plusplus''.
  * The ''%%__STDC__%%'' variable is defined when compiling a C program, and may also be defined when compiling C++.

====GCC-specific variables====

The following are GCC-specific variables.  While they are not specifically preprocessor macros they are [[http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html|magic]] and can be used the same way:

  * ''%%__func__%%'' contains the bare name of the function
  * ''%%__FUNCTION__%%'' is another name for ''%%__func__%%''
  * The ''%%__PRETTY_FUNCTION__%%'' contains the type signature of the function as well as its bare name.