C# cannot take new memory -

working c# - c++ (manage) mix project , realize there memory leaks in our project, searched , found out, destructor of c++ part never called wrote piece of code free memories. can see program growing slower in memory (there more memory leaks), problem is, in c# part program start crash because of "out of memory exception". in operation such as

double []k = new double[65536]; 

memory usage of program seems 400-500mb crashed.
os : win server 2003
memory : 4 gb
os should let program grow 1200 mb after wrote free memory part start crash 400-500mb.
called c++ func c# part free memories

freememories() {    if(!misalreadyfreedmemory)    {       misalreadyfreedmemory = true;       _aligned_free(pointera);       _aligned_free(pointerb);        ....     } } 

why cannot take new memory, program can not take released memory again?

you should use idisposable pattern objects. basic idea this:

public class myobject : idisposable {     // unmanaged resource:     unmanagedresource unmanaged;      // finalizer:     ~myobject     {         disposeunmanaged();     }      public void dispose()     {         disposemanaged();         disposeunmanaged();         gc.suppressfinalize(this);     }      protected virtual disposemanaged()     {         // dispose _managed_ resources here.     }      protected virtual disposeunmanaged()     {         // dispose _unmanaged_ resources here.         this.unmanaged.freeme();         this.unmanaged = null;     } } 

then can call dispose on object you're sure no longer needed, , unmanaged memory freed.

myobject obj; obj.dispose(); 

or, if forget call dispose, unmanaged resources freed when object collected garbage collector (through finalizer).