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Posted 2 Nov 2004

AGM::LibReflection: A reflection library for C++.

, 2 Nov 2004
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Description of the library AGM::LibReflection.


LibReflection is a little library (well, a header to be specific) that gives reflection capabilities to C++ classes. When we talk about reflection, we don't mean just RTTI, but a rich palette of capabilities useful in every day programming:

  • specify and examine class inheritance
  • declare and examine normal and static fields
  • declare and examine normal, virtual, and static methods
  • declare and use properties and events
  • set and get field values
  • call methods and get results
  • create instances without having the headers at hand, by using a class registry

And all the above almost happen automatically, with very few macros that the programmer has to put in the application's classes...and you also get the added benefit of class properties and events, something that C++ does not provide by default.


Using LibReflection is very easy. The following piece of code shows a class with fields, properties and methods, all reflected in the class' Class object:

//what you need to include
#include "reflection.hpp"

//namespace usage
using namespace agm::reflection;

//example base class
class Base {
    //needed so as that the class gets reflection capabilities
    CLASS(Base, NullClass);

    //a reflected property
    PROPERTY(int, length);

    //a reflected method
    METHOD(public, bool, processLength, (int l));

    //a reflected field
    FIELD(private, int, m_length);

    //property getter
    int get_length() const {
        return m_length;

    //property setter
    void set_length(int l) {
        m_length = l;

//a reflected method implementation
bool Base::processLength(int l)
    return l == m_length;

//a derived class
class Derived : public Base {
    //derived reflected class
    CLASS(Derived, Base);

//for the demo
#include <iostream>
using namespace std;

int main()
    //a class instance
    Derived derived;

    //get the class of the Derived class
    const Class &derived_class = derived.getClass();

    //print the class name
    cout << derived_class.getName() << endl;

    //print the the m_length field
    const Field &length_field = derived_class.getField("m_length");
    cout << length_field.getType() << " " 
         << length_field.getName() << endl;

    //print the the length property
    const Property &length_prop = derived_class.getProperty("length");
    cout << length_prop.getType() << " " 
         << length_prop.getName() << endl;

    //print the 'processLength()' method
    const Method &process_length_method = 
    cout << process_length_method.getType() << " "
         << process_length_method.getName()
         << process_length_method.getArgs()
         << endl;

    //set the length property
    cout << "using length property" << endl;
    length_prop.set(&derived, 10);
    int i;
    length_prop.get(i, &derived);
    cout << "length = " << i << endl;

    //calling the length method
    cout << "calling bool Base::processLength(int)" << endl;
    bool b;
    process_length_method.invoke(b, (Base *)&derived, 10);
    cout << "processLength=" << b << endl;

    return 0;


For more information, you can check out my little site here.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Achilleas Margaritis
Software Developer (Senior)
Greece Greece
No Biography provided

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Comments and Discussions

Generaltypeless parameters Pin
Member 1811246-Oct-08 6:26
memberMember 1811246-Oct-08 6:26 
GeneralWindows CE compilation Pin
DuvidaCruel9-Feb-07 10:11
memberDuvidaCruel9-Feb-07 10:11 
GeneralLibReflection for gcc Pin
Anonymous3-May-05 5:51
sussAnonymous3-May-05 5:51 
QuestionArrays? Pin
neo26007776-Apr-05 10:30
memberneo26007776-Apr-05 10:30 
GeneralAn Update Version Posted Pin
my203829-Mar-05 8:52
membermy203829-Mar-05 8:52 
GeneralNew Changes Made to LibReflection Pin
my203823-Mar-05 11:22
membermy203823-Mar-05 11:22 
GeneralRe: New Changes Made to LibReflection Pin
WREY28-Mar-05 1:14
memberWREY28-Mar-05 1:14 
GeneralRe: New Changes Made to LibReflection Pin
my203828-Mar-05 7:40
membermy203828-Mar-05 7:40 
GeneralNot totally true. Pin
WREY28-Mar-05 9:23
memberWREY28-Mar-05 9:23 
GeneralRe: Not totally true. Pin
my203829-Mar-05 8:53
membermy203829-Mar-05 8:53 
GeneralCompile Error in VS.NET 1.1 Pin
colormegjian22-Mar-05 4:26
membercolormegjian22-Mar-05 4:26 
GeneralRe: Compile Error in VS.NET 1.1 Pin
tomthorne22-Apr-05 8:23
membertomthorne22-Apr-05 8:23 
GeneralRe: Compile Error in VS.NET 1.1 Pin
derchoff6-Oct-05 1:15
memberderchoff6-Oct-05 1:15 
QuestionCan i use it in BCB? Pin
FlameBlade17-Feb-05 3:41
memberFlameBlade17-Feb-05 3:41 
GeneralContact Pin
psyclonist (Stephan K.)22-Nov-04 2:41
susspsyclonist (Stephan K.)22-Nov-04 2:41 
QuestionCan Instance be Created Dynamicly? Pin
Laisser21-Nov-04 7:21
memberLaisser21-Nov-04 7:21 
GeneralVery Interesting! Pin
ggerules10-Nov-04 6:19
memberggerules10-Nov-04 6:19 
GeneralCool! Pin
Jim Crafton2-Nov-04 15:15
memberJim Crafton2-Nov-04 15:15 
GeneralRe: Cool! Pin
axilmar3-Nov-04 3:37
memberaxilmar3-Nov-04 3:37 
GeneralRe: Cool! Pin
my203815-Mar-05 11:27
membermy203815-Mar-05 11:27 
GeneralDude Pin
armentage2-Nov-04 10:23
memberarmentage2-Nov-04 10:23 
GeneralRe: Dude Pin
axilmar2-Nov-04 10:42
memberaxilmar2-Nov-04 10:42 
GeneralRe: Dude Pin
Dave Handley3-Nov-04 7:10
memberDave Handley3-Nov-04 7:10 
Unfortunately, there are lots of reasons for NOT using the CLR, be it with Managed C++ or C# (and also for not using Java) - but in those cases Reflection can still be very useful.

Some of the reasons why I haven't been able to use Managed C++ or C# (despite incentive to try) include:

1) Immature libraries. Because the languages haven't been around very long, the libraries have a huge number of weaknesses - the last time I tried to use C# I found that I couldn't create a directory browser from the file dialog since the file dialog didn't include that feature and it was a final class. In C++ I would simply inherit off CFileDialog.

2) The syntax is impenetrable. Managed C++ has improved slightly with the newer work Microsoft has done, but it is still nowhere near as clear as well written C++.

3) The syntax is non-standard. Except in the rare cases where the CLR exists for other platforms and compilers, you are stuck with VC++ and Windows.

4) The CLR is incredibly slow compared to raw C++. Because you are working through an intermediate language, and you have the overhead of garbage collection and smart pointers, for time critical applications Managed C++ just doesn't hold up. I write CAD applications for a living and Managed C++ just wouldn't cut it.

5) It is very difficult to use Managed and Unmanaged code side by side. Again, last time I checked, ALL your code had to be recompiled with the compiler switch for CLR included. That scares me because calls from unmanaged code into managed code are going to have loads on non-deterministic wrappers around them.

I'll get off my soapbox now - but suffice it to say that I haven't been impressed with the CLR - and it certainly doesn't remove the need to provide decent reflection libraries under certain circumstances in C++.

Good work on AGM::LibReflection.

GeneralRe: Dude Pin
Anders Dalvander13-Nov-04 3:03
memberAnders Dalvander13-Nov-04 3:03 
GeneralRe: Dude Pin
Dave Handley13-Nov-04 4:08
memberDave Handley13-Nov-04 4:08 

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