Distinguish between managed module and unmanaged module.

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

trialproduct2004@yahoo.com - 28 Jun 2006 12:27 GMT

Hi all,

Can someone tell me how OS makde differentation betwen managed module
and unmanaged module.

Means say suppose i developed one exe in MFC and one in .net. How Os
recognise that second exe require .net framework. Means which part of
exe is consider while determining whether exe need .net framework or
not.

Please correct me if i am wrong.

thanks in advance.

Reply to this Message

Ben Voigt - 28 Jun 2006 13:53 GMT

> Hi all,
>
[quoted text clipped - 5 lines]
> exe is consider while determining whether exe need .net framework or
> not.

.NET PE applications have a static dependency on mscoree.dll (and no other
DLLs). Since a pure/safe/verifiable module can have no native entry point,
we can conclude that the .NET PE has no native entry point (no runtime
initialization, no WinMain). However, the OS loader must load all
dependencies before launching the application. Presumably the mscoree.dll
DllMain routine modifies the process descriptor in some way to cause the
process to start running in mscoree. If an empty entry point is allowed for
the exe, it might be as simple as spawning a new thread in mscoree, but
considering most functions are forbidden in DllMain (loader lock and all),
mscoree DllMain must not be the main routine. kernel32.dll, which contains
the CreateThread function, is the only static dependency of mscoree.

> Please correct me if i am wrong.
>
> thanks in advance.

Reply to this Message

trialproduct2004@yahoo.com - 28 Jun 2006 15:04 GMT

Hi,

thanks for your reply.

CAn you elaborate things slightly so that i can get exact idea about
it.

I only know that in idata section of exe it contain import statemnet
for importing dll mscoree.dll. It is means that in normal dll build in
vb6 or mfc this dll is not getting used.

Can u tell me steps getting followed by loaded while loading .net exe
and normal exe like exe developed in mfc or vb6.

Or please tell me difference between these file format by which os get
idea that this exe require .net framework and other one not.

Is it like in idata second there is coreexemain function which is
imported from mscoree.dll so when loader try to load exe it will check
try to call this function for .net exe and what if exe is developed in
unmanaged code then which function loader try to call is it winmain?

Please correct me if i am wrong.

Thanks in advance.

> > Hi all,
> >
[quoted text clipped - 21 lines]
> >
> > thanks in advance.

Reply to this Message

Ben Voigt - 28 Jun 2006 15:49 GMT

> Hi,
>
[quoted text clipped - 17 lines]
> try to call this function for .net exe and what if exe is developed in
> unmanaged code then which function loader try to call is it winmain?

The OS loader does not check for managed .exe. It does not do anything
special. For all applications, the loader first loads all static
dependencies, running each DllMain function, then checks the PE header for a
native entry point, which it runs if it finds one.

With a managed application, when mscoree's DllMain executes, it starts up
CLR hosting (probably on a new thread which runs outside loader lock) which
get the handle to the running process, reads the metadata tables, finds the
managed entry point type, JIT compiles and executes static constructors and
then the managed main method. The managed .exe is missing any native entry
point... if it had one, it would not be pure MSIL.

> Please correct me if i am wrong.
>
[quoted text clipped - 30 lines]
>> >
>> > thanks in advance.

Reply to this Message

Rate this thread:

Distinguish between managed module and unmanaged module.

Free Magazines