Ihave a dll program that compiles with no warnings or errors.  It is compiled
with the options:
dmc.exe -mn -c   -x -WD -w-

and linked with the options:
link.exe /NOLOGO /DELEXECUTABLE /EXETYPE:NT /SUBSYSTEM:WINDOWS

The calling program uses explicit linking with LoadLibrary and GetProcAddress. Both of these functions execute without getting an error.  But the DllMain function is never called.  I put a messagebox in the DllMain function to verify this.

Why isn't the DllMain function being called????

In article <doc7a5$2veo$1@digitaldaemon.com>, JimP says...
>
>Ihave a dll program that compiles with no warnings or errors.  It is compiled
>with the options:
>dmc.exe -mn -c   -x -WD -w-
>
>and linked with the options:
>link.exe /NOLOGO /DELEXECUTABLE /EXETYPE:NT /SUBSYSTEM:WINDOWS
>
>The calling program uses explicit linking with LoadLibrary and GetProcAddress. Both of these functions execute without getting an error.  But the DllMain function is never called.  I put a messagebox in the DllMain function to verify this.
>
>Why isn't the DllMain function being called????
>
>


I tried this with the Borland and GCC (MinGW) compilers.  It worked OK with both.  It must be something about the Digital Mars compiler.  An option? Something I am omitting?  Or is it just not executed with explicit linking?

Any suggestions would be appreciated.

"JimP" <JimP_member@pathlink.com> wrote:

> I tried this with the Borland and GCC (MinGW) compilers.  It worked OK with
> both.  It must be something about the Digital Mars compiler.  An option?
> Something I am omitting?  Or is it just not executed with explicit linking?

How did you declare DllMain()?

--gv

In article <dojkr4$gum$1@digitaldaemon.com>, Gisle Vanem says...
>
>"JimP" <JimP_member@pathlink.com> wrote:
>
>> I tried this with the Borland and GCC (MinGW) compilers.  It worked OK with both.  It must be something about the Digital Mars compiler.  An option? Something I am omitting?  Or is it just not executed with explicit linking?
>
>How did you declare DllMain()?
>
>--gv

I have the same problem - neither DllMain, nor constructors for global objects are executed. I am making a C++ DLL that should be loaded by LoadLibrary call. Here is a sample code:

// dll.cpp
#include<windows.h>

extern "C" BOOL WINAPI DllMain(HINSTANCE hinst,DWORD reason,LPVOID lpReserved)
{
MessageBox(NULL,"DllMain","dll",MB_OK);
return TRUE;
}

// Global object
class TSomeClass
{ public:
int i;
TSomeClass(void){MessageBox(NULL,"Constructor","dll",MB_OK);};
};
TSomeClass SomeObject;

// Function
extern "C" __declspec(dllexport)
int CALLBACK DoSomething(int CallMode,LPVOID Data,LPVOID ExtParam)
{ static BOOL FirstCall=TRUE;
if(FirstCall)
{ FirstCall=FALSE;
MessageBox(NULL,"Function","dll",MB_OK);
}
return 0;
}

The compiler command line:
c:\prog\dm\bin\dmc.exe dll.cpp -c -mn -WD -Ae -I"c:\prog\dm\include"
-I"c:\prog\dm\include\Win32"
Linker command line:
c:\prog\dm\bin\link.exe /DELEXECUTABLE /NODEBUG /EXETYPE:NT dll.obj ,
testdll.dll , , user32.lib kernel32.lib

Everything compiles without errors. When I call LoadLibrary I see neither "DllMain" message, nor "Constructor" message, but function DoSomething executes normally and produces "Function" message at first call.

I tried to add "/ENTRY:_DllMainCRTStartup" linker switch as I've seen in some examples, but nothing changes.

Please tell me what am I doing wrong.

Alex Roschin wrote:
> Please tell me what am I doing wrong.

I took my code from:
http://home20.inet.tele.dk/midgaard/tipwin20060212.html

And changed the source code for the dll to:
#include <windows.h>
#include "mydll.h"

class DllClass
{
public:
   DllClass()
   {
      MessageBox(0, "Hello World", "DllClass", MB_OK);
   }
};

DllClass DllObject;

__declspec(dllexport) BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
{
   switch (ul_reason_for_call)
   {
   case DLL_PROCESS_ATTACH:
   case DLL_THREAD_ATTACH:
   case DLL_THREAD_DETACH:
   case DLL_PROCESS_DETACH:
      MessageBox(0, "Something", "DllMain", MB_OK);
      break;
   }
   return TRUE;
}

__declspec(dllexport) int DoSomething(int a, int b)
{
   return a*b*2;
}

__declspec(dllexport) Whatever::Whatever(int aX, int aY) : X(aX), Y(aY)
{
}

__declspec(dllexport) int Whatever::Get()
{
   return X*Y;
}

And build with these commands:
dmc -mn -WD mydll.cpp kernel32.lib
implib.exe /noi mydll.lib mydll.dll
dmc mytest.cpp mydll.lib

And the MessageBox'es popup as expected.

It can be noted that I don't use LoadLibrary, but use the
dll throug a .lib created by implib.exe. I don't know
if it will make any difference.

-- 
Absolutely not the best homepage on the net:
http://home20.inet.tele.dk/midgaard
But it's mine - Bertel

In article <e0bupn$2v9n$1@digitaldaemon.com>, Bertel Brander says...
>I took my code from: http://home20.inet.tele.dk/midgaard/tipwin20060212.html

Thank you! I've found the thing that caused the problem:

1) When I compile and link the example with the single command (without "-c"
option), everything works fine - I see all message boxes.

2) When I try to compile and to link separately with
dmc.exe -c -mn -WD mydll.cpp
link.exe mydll.obj , testdll.dll , , kernel32.lib
neither DllMain, nor constructor message boxes show up.

I believe that in first case dmc.exe calls link.exe with certain options which I don't know. I tried to play with some, but in vain.

Since the single command build works fine, I think I will use it.

Thanks again.

Alex Roschin пишет:

> In article <e0bupn$2v9n$1@digitaldaemon.com>, Bertel Brander says...
>> I took my code from:
>> http://home20.inet.tele.dk/midgaard/tipwin20060212.html
> 
> Thank you! I've found the thing that caused the problem:
> 
> 1) When I compile and link the example with the single command (without "-c"
> option), everything works fine - I see all message boxes. 
> 
> 2) When I try to compile and to link separately with
> dmc.exe -c -mn -WD mydll.cpp
> link.exe mydll.obj , testdll.dll , , kernel32.lib
> neither DllMain, nor constructor message boxes show up. 
> 
> I believe that in first case dmc.exe calls link.exe with certain options which I
> don't know. I tried to play with some, but in vain. 
> 
> Since the single command build works fine, I think I will use it.
> 
> Thanks again.
> 
> 
It seems that OPTLINK will not generate valid DLL when .def is not specified.

DMC.EXE in fact generates simple .DEF and supplies it to linker:

LIBRARY "tasklet.dll"
DESCRIPTION 'tasklet'
EXETYPE NT
SUBSYSTEM WINDOWS
CODE SHARED EXECUTE
DATA WRITE

Neither LIBRARY, nor CODE SHARED cannot be specified with OPTLINK switches, hence I think they (or their absence) are cause of troubles.


Nic Tiger.

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