DLC Toolkit homepage
Welcome to the Dynamically Linked Class toolkit
This page is hosted thanks to SourceForge.net's help so please support them as they support us :
This page is no longer maintained. An up-to-date version of DLC is now hosted
in Massive G Engine's CVS repository
Examples using DLC and a Doxygen config file to build the documentation might
still be retrieved in the archive on DLC's
project page on SourceForge.
Be warned though that the two main DLC files in that archive (dlc.h and
dlcDynamic.h) are outdated so don't mess up with versions.
What DLC is about...
DLC is a small toolkit for C++ developpers willing to dynamically load classes in their program. It
currently works fine on Windows and x86 Linux platforms. It supposedly works on other Linux-flavour
platforms but hasn't been tested yet. Please report if you tried it on another platform.
It consists of two header files dlc.h and dlcDynamic.h. The file dlc.h declares the pure static
template class dlc<...> and some preprocessor macros for instantiating that class and declaring
dynamic classes. The file dlcDynamic.h declares the DLC_DYNAMIC macro which can be used to
automatically import or export symbols, including classes, when you want your program to compile on
Windows. The only thing the programmer has to do is to indicate wich component is being compiled and
wich component is being declared by defining a value for DLC_COMPILED_COMPONENT and
How it works...
Dynamic classes have to be compiled in a dynamic library (.dll for Windows, .so for Linux) named
after the name of the class (i.e. "my_class.so" for class "my_class"). They have to inherit from an
interface class (rather a pure virtual one) chosen by the user and wich will be used as first
argument of the dlc template class.
The instantiated dlc template class will then provide a direct map between the name of the class
(stored in a C character string) and a way to build an object of that class, even without linking
the so-called class to the program using it. Only the interface class has to be known when building
Since there is no general way to map a C++ method name to it's name inside the library, the toolkit
uses a factory function exported into the library in a C-style so as to be able to retrieve the
address of that function. A factory function is a function returning the address of a newly built
object. The fact that it is externally a C-style function doesn't actually mean that its code is
not in C++. Many papers can be found on the Internet explaining this process. However, heritage
between dynamic classes for now is only possible by compiling the classes with the same
Once your classes are build, it is possible to retrieve the address of a new object of any of those
classes through the method
dlc<interface_class, n_args, args_types>( "class_name", factory_args ).
The DLC toolkit is released under the terms of the GNU Lesser General Public
Its documentation is released under the GNU Free Documentation License.