Skip to main content

A Note On Finalize !!!

This is not about what Finalize is, but well Finalize is the last call on a managed object, where you can perform some clean up operations, before getting garbage collected by the .NET runtime. A few important things that are to be noted about finalizers are:-

- In C#, finalizers are represented by the ~ClassName [destructor syntax], and the Object.finalize can neither be overridden or called directly. It cannot be called directly because it is protected. The destructors in C# also take care of calling the dtor of the base class.
- Finalizer is called on an object only once, just before the .NET runtime attempts to garbage collect the object.
- Finalizers can be called anytime on a managed object that is not being referenced, and on any thread by the .NET runtime.
- The order in which the finalizers are called is also not fixed. Even when two objects are related to each other in some way, there is no hierarchial order in which the finalizers for the objects will be called.
- During an application shutdown, finalizers will be called even on objects that are still accessible.

The most interesting part of the finalizer is not when it is called but when all is it NOT called. This is where we need to watch and rely on the Dipose method [IDispoable - Dispose pattern].

- When a finalizer of a object blocks indefinitely [deadlock, infinite loop etc].
- When the process terminates improperly without giving the .NET runtime a chance run the finalizers.
- When a managed object is exempt from finalization by calls like GC.SupressFinalize or KeepAlive.
Post a Comment

Popular posts from this blog

Passing CComPtr By Value !!!

This is about a killer bug identified by our chief software engineer in our software. What was devised for ease of use and write smart code ended up in this killer defect due to improper perception. Ok, let us go!CComPtr is a template class in ATL designed to wrap the discrete functionality of COM object management - AddRef and Release. Technically it is a smart pointer for a COM object.void SomeMethod() { CComPtr siPtr; HRESULT hr = siPtr.CoCreateInstance(CLSID_SomeComponent); siPtr->MethodOne(20, L"Hello"); }Without CComPtr, the code wouldn't be as elegant as above. The code would be spilled with AddRef and Release. Besides, writing code to Release after use under any circumstance is either hard or ugly. CComPtr automatically takes care of releasing in its destructor just like std::auto_ptr. As a C++ programmer, we must be able to appreciate the inevitability of the destructor and its immense use in writing smart code. However there is a difference between …

out, ref and InvokeMember !!!

When I was working on the .NET reflection extravaganza thing that I explained in my previous column, i learnt one another interesting thing, that is about the Type.InvokeMember. How will pass out or ref parameters for the method invoked using Type.InvokeMember ? If you are going to invoke a method with the prototypeint DoSomething(string someString, int someInt);then you would use InvokeMember like this:-object obj = someType.InvokeMember("DoSomething",
BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
null,
this,
new object[] {"Largest Integer", 1});or use some variables in the new object[] {...}. But what do you with the args if DoSomething takes out or ref parameters ?int DoSomething(out string someString, ref int someInt);Something like this will not work string someText = string.Empty;
int someInt = 0;
object obj = someType.InvokeMember("DoSomething",
BindingFlags.Public | BindingFlags.NonPublic …

Offering __FILE__ and __LINE__ for C# !!!

THIS POST USES SYNTAXHIGHLIGHTER AND HAS ISSUES RENDERING CODE ONLY IN CHROME
Not the same way but we could say better.
Visual Studio 2012, another power packed release of Visual Studio, among a lot of other powerful fancy language features, offers the ability to deduce the method caller details at compile time.
C++ offered the compiler defined macros __FILE__ and __LINE__ (and __DATE__ and __TIME__), which are primarily intended for diagnostic purposes in a program, whereby the caller information is captured and logged. For instance, using __LINE__ would be replaced with the exact line number in the file where this macro has been used. That sometimes beats the purpose and doesn't gives us what we actually expect. Let's see.

For instance, suppose you wish to write a verbose Log method with an idea to print rich diagnostic details, it would look something like this.
void LogException(const std::string& logText, const std::string& fileName, …