DllMain

[=?Utf-8?B?R2Vvcmdl?=]

Hello everyone,
From MSDN,

http://msdn2.microsoft.com/en-us/library/ms682583.aspx

parameter fdwReason of DllMain has four values,

DLL_PROCESS_ATT ACH
DLL_PROCESS_DET ACH
DLL_THREAD_ATTA CH
DLL_THREAD_DETA CH

I think we could simply understand what MSDN described about the four values
in the following way after some experiment (I have read the big table and
want to extract some brief and simple information to understand to remember),

DLL_PROCESS_ATT ACH: will be called only once when the process loads the DLL
for the 1st time
DLL_PROCESS_DET ACH: will be called only once when the process unloads the
DLL (when process stops)
DLL_THREAD_ATTA CH: will be called every time when a thread inside the
current process loads the DLL
DLL_THREAD_DETA CH: will be called every time when a thread inside the
current process unloads the DLL

Is that correct understanding?
thanks in advance,
George

[=?Utf-8?B?R2Vvcmdl?=]

Thanks for your confirmation, Ben!
regards,
George

"Ben Voigt [C++ MVP]" wrote:

>
"George" <Ge****@discuss ions.microsoft. comwrote in message
news:E3******** *************** ***********@mic rosoft.com...

Thanks Ben,
I think you mean if we have already load the library, if we call
LoadLibrary
again and again, the DllMain will not be called again and again since the
reference counter is already >1, right?

But if the process unloads the DLL (make reference counter to 0), then
LoadLibrary again, the DllMain will be called again with
DLL_PROCESS_ATT ACH
value, right?

I think that is correct, yes.

regards,
George

"Ben Voigt [C++ MVP]" wrote:

>
"George" <Ge****@discuss ions.microsoft. comwrote in message
news:92******** *************** ***********@mic rosoft.com...
Hello everyone,
From MSDN,

http://msdn2.microsoft.com/en-us/library/ms682583.aspx

parameter fdwReason of DllMain has four values,

DLL_PROCESS_ATT ACH
DLL_PROCESS_DET ACH
DLL_THREAD_ATTA CH
DLL_THREAD_DETA CH

I think we could simply understand what MSDN described about the four
values
in the following way after some experiment (I have read the big table
and
want to extract some brief and simple information to understand to
remember),

DLL_PROCESS_ATT ACH: will be called only once when the process loads the
DLL
for the 1st time
DLL_PROCESS_DET ACH: will be called only once when the process unloads
the
DLL (when process stops)

No, these are wrong (others have explained the THREAD messages).

If LoadLibrary and FreeLibrary are used, then DLL_PROCESS_ATT ACH is
called
each time the use count changes from 0 to 1 and DLL_PROCESS_DET ACH is
called
each time the use count changes from 1 to 0. This could happen multiple
times in a single run.