title: AspectC++
text: # AspectC++
  
  AspectC++ is an aspect-oriented extension of C and C++ languages. It has a source-to-source compiler, which translates AspectC++ source code into compilable C++. The compiler is available under the GNU GPL, though some extensions specific to Microsoft Windows are only available through pure-systems GmbH.
  
  Aspect-oriented programming allows modularizing cross-cutting concerns in a single module, an aspect. Aspects can modify existing classes, but most commonly they provide 'advice' that runs before, after, or around existing functionality.
  
  ## Example
  
  All calls to a specific function can be traced using an aspect, rather than inserting 'cerr' or print statements in many places:
  
  The Tracer aspect will print out a message before any call to %Iter::Reset. The %Iter syntax means that it will match all classes that end in Iter.
  
  Each 'matched' location in the source code is called a join point—the advice is joined to (or advises) that code. AspectC++ provides a join point API to provide and access to information about the join point. For example, the function:
  
  returns the name of the function (that matched %Iter::Reset) that is about to be called.
  
  The join point API also provides compile-time type information that can be used within an aspect to access the type or the value of the arguments and the return type and return value of a method or function.
  
  