Can DLL produce a message after loading executable?

[Maya]

Good Evening All,
As far as I know, DLL can be launched using attached/detach process or thread.
Is it possible for attached DLL, to wait for an Executable window, then after that, generates "Hello World" Message?

[Olli]

Good evening All,
As far as I know, DLL can be launched using attached/detach process or thread.

No !
A DLL file can be launched, using LoadLibrary().

[LOAD] ---> [Execute AttachProcess() if it exists]

Let us bypass threads for now. Even if it is not very complex : it is a similar calling concept. Let us stay to the main load of a library.

Is it possible for attached DLL, to wait for an Executable until it completely loaded in memory, then after that only, it generates "Hello World" Message?

What does this executable completely load in memory ?
-> its own memory buffer ?
-> its own file total content ?
-> the DLL it has loaded ?

The executable must send a flag. For example, call a specific function in the DLL.

[Maya]

Hi,
DLL is attached to the Executable using one of the "attach/detach process/thread" methods (not sure which one).

Is the following sequence possible?

1- Executable starts.
2- DLL starts but doesn't do anything (waiting executable to be fully loaded).
3- Executable main window appears on the Desktop (fully loaded).
4- DLL generates "Hello World" Message over the Executable main window.

[wombats]

Code: Select all

ProcedureDLL AttachProcess(Instance)
  MessageRequester("", "Attach")
EndProcedure

That pops up the message requester when I open the library.

[Maya]

Code: Select all

ProcedureDLL AttachProcess(Instance)
  MessageRequester("", "Attach")
EndProcedure

That pops up the message requester when I open the library.

Hi,
"AttachProcess" pops up the Message, then it disappeared, then after, the main window appears, which is not the required sequence.

[DarkDragon]

Code: Select all

ProcedureDLL AttachProcess(Instance)
  MessageRequester("", "Attach")
EndProcedure

That pops up the message requester when I open the library.

Hi,
"AttachProcess" pops up the Message, then it disappeared, then after, the main window appears, which is not the required sequence.

You could create a thread in attach, wait for the required objects to be there (Window) and execute it then. However the better way would be to have some init function called from inside the main executable.

[Maya]

Code: Select all

ProcedureDLL AttachProcess(Instance)
  MessageRequester("", "Attach")
EndProcedure

That pops up the message requester when I open the library.

Hi,
"AttachProcess" pops up the Message, then it disappeared, then after, the main window appears, which is not the required sequence.

You could create a thread in attach, wait for the required objects to be there (Window) and execute it then. However the better way would be to have some init function called from inside the main executable.

You are right, the solution in the 'Threads', but unfortunately, I have no idea about it.
Could you please write me a sample.
Thank you!

[mk-soft]

Write your own ProcedureDLL InitDLL() and call it after creating the window.

[Maya]

... call it after creating the window.

I wish I can do this by the DLL itself.

[Olli]

No, you cannot. An explicite flag must be passed in the executable source :

Code: Select all

; blabla
; code before the executable wants to tell the DLL.
tellTheDLL()
; code after the executable have told the DLL

DLL source :

Code: Select all

ProcedureDLL tarteAuxPoireaux()
EndProcedure

ProcedureDLL tellTheDLL()
 MessageRequester("Uh?", "The DLL received a call from the executable, by simply executing this procedure.")
EndProcedure

[Smitis]

Is it possible for attached DLL, to wait for an Executable window, then after that, generates "Hello World" Message?

Use SetWinEventHook from AttachProcess and track the creation of windows

Code: Select all

hCBTHook = SetWindowsHookEx_(#WH_CBT,@CBTProc(),#Null,GetCurrentThreadId_())

[Maya]

Thank you all for the great support.
I wish I can do that using the "Threads".