Hello

I'm trying to make a simple windows GUI application using D.
First, I used DMD, and I suffered a lot due to it's OMF format. So I decided
to switch to GDC (with MinGW). But I still receive linking errors related to
Phobos :-(

Are there any examples or tutorials that can help in this area? I.e. ones that show how to set the GC correctly... There are such examples for DMD, but I couldn't find similar examples for GDC... So any help?

Thanks
john

Johnny wrote:
> Hello
> 
> I'm trying to make a simple windows GUI application using D.
> First, I used DMD, and I suffered a lot due to it's OMF format. So I decided
> to switch to GDC (with MinGW). But I still receive linking errors related to
> Phobos :-(
> 
> Are there any examples or tutorials that can help in this area? I.e. ones
> that show how to set the GC correctly... There are such examples for DMD,
> but I couldn't find similar examples for GDC... So any help?
> 
> Thanks
> john
> 
> 
> 

If you are linking with other libraries, you may need to explicitly link against -lgphobos with that library early on the command line:

gdc a.o b.o -lgphobos -lwsock32

If you do not need a custom WinMain, just write the normal D main(). Otherwise, the easiest thing to do is call _d_run_Dmain:

---
import std.c.windows.windows;
extern (C) int _d_run_Dmain(int argc, char **argv);
extern (Windows)
int WinMain(HINSTANCE hInstance,
        HINSTANCE hPrevInstance,
        LPSTR lpCmdLine,
        int nCmdShow)
{
    char * fake_argv ="x";
    return _d_run_Dmain(1, & fake_argv);
}

int main(char[][] args) {
  return 0;
}
---

David

David,

It's still not working with me; I must have something wrong in my code or in my MinGW/GDC installation.

Here is a simple example that I tried to compile with GDC 0.23. I really wish not only to correct the problem, but to understand exactly what's going wrong:


Compilation Steps:
-----------------
1- $ gdc -c -v WinMenu.d  (OK)

	Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
	Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc
--disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32
--with-gnu-ld --with-gnu-as --enable-threads --disable-nls
--disable-win32-registry --disable-shared --enable-sjlj-exceptions
	Thread model: win32
	gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
	 c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet
-dumpbase WinMenu.d -auxbase WinMenu -version -iprefix
c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o
g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s
	GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
			compiled by GNU C version 3.4.2 (mingw-special).
	GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
	 c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe
-o WinMenu.o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s


2- $ gdc -v -Wall -o  WinMenu-gdc.exe WinMenu.d -lgphobos  (Link errors)

	Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
	Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc
--disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32
--with-gnu-ld --with-gnu-as --enable-threads --disable-nls
--disable-win32-registry --disable-shared --enable-sjlj-exceptions
	Thread model: win32
	gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
	 c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet
-dumpbase WinMenu.d -auxbase WinMenu -Wall -version -iprefix
c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o
g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
	GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
			compiled by GNU C version 3.4.2 (mingw-special).
	GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
	 c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe
-o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o
g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
	 c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/collect2.exe -Bdynamic -o
WinMenu-gdc.exe /mingw/lib/crt2.o
c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtbegin.o
-Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5 -Lc:/MinGW/bin/../lib/gcc
-L/gdc/lib/gcc/mingw32/3.4.5
-Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/lib
-L/mingw/lib -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../..
-L/gdc/lib/gcc/mingw32/3.4.5/../../..
g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o -lgphobos -lgphobos
-lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt -luser32 -lkernel32
-ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt
c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtend.o
	/mingw/lib/libgphobos.a(cmain.o):(.text+0x19): undefined reference to
`_Dmain'
	collect2: ld returned 1 exit status


It seems that the Phobos library itself refers to _Dmain and linker can't find it, so where is _Dmain, and why isn't it found?


The source code file is attached.

Thanks
john



David Friedman wrote:
> Johnny wrote:
>> Hello
>>
>> I'm trying to make a simple windows GUI application using D.
>> First, I used DMD, and I suffered a lot due to it's OMF format. So I
>> decided
>> to switch to GDC (with MinGW). But I still receive linking errors
>> related to
>> Phobos :-(
>>
>> Are there any examples or tutorials that can help in this area? I.e. ones that show how to set the GC correctly... There are such examples for DMD, but I couldn't find similar examples for GDC... So any help?
>>
>> Thanks
>> john
>>
>>
>>
> 
> If you are linking with other libraries, you may need to explicitly link against -lgphobos with that library early on the command line:
> 
> gdc a.o b.o -lgphobos -lwsock32
> 
> If you do not need a custom WinMain, just write the normal D main(). Otherwise, the easiest thing to do is call _d_run_Dmain:
> 
> ---
> import std.c.windows.windows;
> extern (C) int _d_run_Dmain(int argc, char **argv);
> extern (Windows)
> int WinMain(HINSTANCE hInstance,
>         HINSTANCE hPrevInstance,
>         LPSTR lpCmdLine,
>         int nCmdShow)
> {
>     char * fake_argv ="x";
>     return _d_run_Dmain(1, & fake_argv);
> }
> 
> int main(char[][] args) {
>   return 0;
> }
> ---
> 
> David

Johnny wrote:
> It seems that the Phobos library itself refers to _Dmain and linker can't find it, so where is _Dmain, and why isn't it found?

"_Dmain" is how the "main" of your program normally gets renamed ("mangled") by the D compiler. It's not found because you didn't write one :).
What happens if you add an empty "void main() {}" ?

I'm pretty sure the Windows version of DMD (or perhaps optlink) will automatically use WinMain instead of main if it sees it, but I'm not sure about GDC/MinGW. Maybe some special command-line option needs to be passed?

Hi Frits

I added the empty main() and the linking succeeds, however, the program does nothing since the entry point (main() )  returns immediately (which is expected.
So may be the good question is how to make GDC accept WinMain as an entry point for Windows GUI programs.

Strangely, I have another simpler GUI program that links correctly with WinMain:

import win32.winbase;
import win32.windef;
import win32.winuser;

extern(Windows) int WinMain(HINSTANCE hInstance,
                        HINSTANCE hPrevInstance,
                        PSTR szCmdLine,
                        int iCmdShow)
{
      MessageBoxA(null, "Hello", "Hello Demo", MB_OK);
      return (0);
}


- Here is how I compile it:

	Administrator@home /cygdrive/c/D-Projects/gdc-test
	$ gdc -c gdctestwin.d -I"C:\dmd"


- Attempting to link with GDC fails:

	Administrator@home /cygdrive/c/D-Projects/gdc-test
	$ gdc -o gdctestwin.exe  gdctestwin.o
	/mingw/lib/libgphobos.a(cmain.o):(.text+0x19): undefined 	reference to `_Dmain'
	collect2: ld returned 1 exit status


- Linking with GCC sycceeds:

	Administrator@home /cygdrive/c/D-Projects/gdc-test
	$ gcc -o gdctestwin.exe  gdctestwin.o


- I tried to use GCC for linking my 1st example, but I get other errors:

	$ gcc -Wall -o WinMenu-gdc.exe WinMenu.o
	WinMenu.o:WinMenu.d:(.text+0xe7): undefined reference to `_D3std6string9toStringzFAaZPa'
	WinMenu.o:WinMenu.d:(.text+0xfb): undefined reference to `_D3std6string9toStringzFAaZPa'
	WinMenu.o:WinMenu.d:(.text+0x152): undefined reference to `CreateWindowA@44'
	WinMenu.o:WinMenu.d:(.text+0x17e): undefined reference to `_d_assert'
	WinMenu.o:WinMenu.d:(.text+0x269): undefined reference to `LOWORD@4'
	WinMenu.o:WinMenu.d:(.text+0x35a): undefined reference to 	`_Dmodule_ref'
	WinMenu.o:WinMenu.d:(.text+0x365): undefined reference to `_Dmodule_ref'
	WinMenu.o:WinMenu.d:(.data+0x48): undefined reference to `_D3std6string12__ModuleInfoZ'
	 WinMenu.o:WinMenu.d:(.data$_D31TypeInfo_E7WinMenu11__anonymous6__initZ[__D31TypeInfo_E7WinMenu11__anonymous6__initZ]+0x0): 	undefined reference to `_D13TypeInfo_Enum6__vtblZ'
WinMenu.o:WinMenu.d:(.data$_D31TypeInfo_E7WinMenu11__anonymous6__initZ[__D31TypeInfo_E7WinMenu11__anonymous6__initZ]+0x8): 	undefined reference to `_D10TypeInfo_i6__initZ'
	collect2: ld returned 1 exit status

- And here I added Phobos, but I get 1st error:

	$ gcc -Wall -o WinMenu-gdc.exe WinMenu.o -lgphobos
	/mingw/lib/libgphobos.a(cmain.o):(.text+0x19): undefined reference to `_Dmain'
	collect2: ld returned 1 exit status

So I'm confused :-( .. what are the definitive steps to compile and link a Windows GUI program using GDC/MinGW?

Regards,
john


Frits van Bommel wrote:
> Johnny wrote:
>> It seems that the Phobos library itself refers to _Dmain and linker can't find it, so where is _Dmain, and why isn't it found?
> 
> "_Dmain" is how the "main" of your program normally gets renamed ("mangled") by the D compiler. It's not found because you didn't write one :).
> What happens if you add an empty "void main() {}" ?
> 
> I'm pretty sure the Windows version of DMD (or perhaps optlink) will automatically use WinMain instead of main if it sees it, but I'm not sure about GDC/MinGW. Maybe some special command-line option needs to be passed?

Johnny,

I had the main/WinMain call order backwards.  So, with the current distribution, I do not think it is possible to get the linker to automatically use whichever of main or WinMain is defined (like DMD does(?))

There is a simple workaround, however:  Use the following command to link.

gdc -o WinMenu-gdc.exe WinMenu.d -lmingw32

This will pull in MinGW's C main() that calls WinMain.  The

Also, you probably want to add -mwindows to the link command line so the .exe will not open a console when run.

David

Johnny wrote:
> David,
> 
> It's still not working with me; I must have something wrong in my code or in my MinGW/GDC installation.
> 
> Here is a simple example that I tried to compile with GDC 0.23. I really wish not only to correct the problem, but to understand exactly what's going wrong:
> 
> 
> Compilation Steps:
> -----------------
> 1- $ gdc -c -v WinMenu.d  (OK)
> 
>     Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
>     Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc --disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32 --with-gnu-ld --with-gnu-as --enable-threads --disable-nls --disable-win32-registry --disable-shared --enable-sjlj-exceptions
>     Thread model: win32
>     gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet -dumpbase WinMenu.d -auxbase WinMenu -version -iprefix c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s
>     GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
>             compiled by GNU C version 3.4.2 (mingw-special).
>     GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
>      c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe -o WinMenu.o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s
> 
> 
> 2- $ gdc -v -Wall -o  WinMenu-gdc.exe WinMenu.d -lgphobos  (Link errors)
> 
>     Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
>     Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc --disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32 --with-gnu-ld --with-gnu-as --enable-threads --disable-nls --disable-win32-registry --disable-shared --enable-sjlj-exceptions
>     Thread model: win32
>     gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet -dumpbase WinMenu.d -auxbase WinMenu -Wall -version -iprefix c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
>     GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
>             compiled by GNU C version 3.4.2 (mingw-special).
>     GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
>      c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/collect2.exe -Bdynamic -o WinMenu-gdc.exe /mingw/lib/crt2.o c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtbegin.o -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5 -Lc:/MinGW/bin/../lib/gcc -L/gdc/lib/gcc/mingw32/3.4.5 -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/lib -L/mingw/lib -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../.. -L/gdc/lib/gcc/mingw32/3.4.5/../../.. g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o -lgphobos -lgphobos -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt -luser32 -lkernel32 -ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtend.o
>     /mingw/lib/libgphobos.a(cmain.o):(.text+0x19): undefined reference to `_Dmain'
>     collect2: ld returned 1 exit status
> 
> 
> It seems that the Phobos library itself refers to _Dmain and linker can't find it, so where is _Dmain, and why isn't it found?
> 
> 
> The source code file is attached.
> 
> Thanks
> john
> 
> 
> 
> David Friedman wrote:
>> Johnny wrote:
>>> Hello
>>>
>>> I'm trying to make a simple windows GUI application using D.
>>> First, I used DMD, and I suffered a lot due to it's OMF format. So I decided
>>> to switch to GDC (with MinGW). But I still receive linking errors related to
>>> Phobos :-(
>>>
>>> Are there any examples or tutorials that can help in this area? I.e. ones
>>> that show how to set the GC correctly... There are such examples for DMD,
>>> but I couldn't find similar examples for GDC... So any help?
>>>
>>> Thanks
>>> john
>>>
>>>
>>>
>>
>> If you are linking with other libraries, you may need to explicitly link against -lgphobos with that library early on the command line:
>>
>> gdc a.o b.o -lgphobos -lwsock32
>>
>> If you do not need a custom WinMain, just write the normal D main(). Otherwise, the easiest thing to do is call _d_run_Dmain:
>>
>> ---
>> import std.c.windows.windows;
>> extern (C) int _d_run_Dmain(int argc, char **argv);
>> extern (Windows)
>> int WinMain(HINSTANCE hInstance,
>>         HINSTANCE hPrevInstance,
>>         LPSTR lpCmdLine,
>>         int nCmdShow)
>> {
>>     char * fake_argv ="x";
>>     return _d_run_Dmain(1, & fake_argv);
>> }
>>
>> int main(char[][] args) {
>>   return 0;
>> }
>> ---
>>
>> David
> 
> 
> ------------------------------------------------------------------------
> 
> import std.c.windows.windows;
> import std.c.stdio;
> import std.string;
> 
> char[] Test_string="You selected Test menu item";
> char[] Hello_string="Hello, my friend";
> char[] Goodbye_string="See you again, bye";
> 
> HINSTANCE hInstance;
> 
> enum {
> 	IDM_TEST=1,
> 	IDM_HELLO,
> 	IDM_GOODBYE,
> 	IDM_EXIT
> }
> 
> 
> int doit() {
> 	hInstance = GetModuleHandleA(null);
> 	
> 	WNDCLASS wc;
> 
> 	wc.lpszClassName = "DWndClass";
> 	wc.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
> 	wc.lpfnWndProc = &WndProc;
> 	wc.hInstance = hInstance;
> 	wc.hIcon = LoadIconA(cast(HINSTANCE) null, IDI_APPLICATION);
> 	wc.hCursor = LoadCursorA(cast(HINSTANCE) null, IDC_CROSS);
> 	wc.hbrBackground = cast(HBRUSH) (COLOR_WINDOW + 1);
> 	wc.lpszMenuName = "TestMenu";
> 	wc.cbClsExtra = wc.cbWndExtra = 0;
> 	RegisterClassA(&wc);
> 	
> 	HWND hWnd;
> 	char[] sClass="My class 0";
> 	char[] sApp="My Application 0";
> 
> 	/+++++
> 	hWnd = CreateWindowA("DWndClass", "Just a window", WS_THICKFRAME |
> 		WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU | WS_VISIBLE,
> 		CW_USEDEFAULT, CW_USEDEFAULT, 400, 300, HWND_DESKTOP,
> 		cast(HMENU) null, hInstance, null);
> 	+++++/
> 
> 	hWnd = CreateWindowA(toStringz(sClass), toStringz(sApp), WS_THICKFRAME |
> 		WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU | WS_VISIBLE,
> 		CW_USEDEFAULT, CW_USEDEFAULT, 400, 300, HWND_DESKTOP,
> 		cast(HMENU) null, hInstance, null);
> 
> 	assert(hWnd);	
> 
> 	ShowWindow(hWnd,SW_SHOWNORMAL);
> 	UpdateWindow(hWnd);
> 
> 	MSG msg;
> 	while (GetMessageA(&msg, cast(HWND) null, 0, 0))
> 	{
> 		TranslateMessage(&msg);
> 		DispatchMessageA(&msg);
> 	}
> 	
> 	return 1;
> }//doit()
> 
> 
> /**********************************************************/
> 
> /* Note the similarity of this code to the console D startup
>  * code in \dmd\src\phobos\dmain2.d
>  * You'll also need a .def file with at least the following in it:
>  *	EXETYPE NT
>  *	SUBSYSTEM WINDOWS
>  */
> 
> extern (C) void gc_init();
> extern (C) void gc_term();
> extern (C) void _minit();
> extern (C) void _moduleCtor();
> extern (C) void _moduleUnitTests();
> 
> extern (Windows)
> int WinMain(HINSTANCE hInstance,
> 	HINSTANCE hPrevInstance,
> 	LPSTR lpCmdLine,
> 	int nCmdShow)
> {
>     int result;
> 
> //    gc_init();			// initialize garbage collector
> //    _minit();			// initialize module constructor table
> 
> /*    try
>     {
> 	_moduleCtor();		// call module constructors
> 	_moduleUnitTests();	// run unit tests (optional)
> 
> 	result = doit();	// insert user code here
>     }
> */
> /*    catch (Object o)		// catch any uncaught exceptions
>     {
> 	MessageBoxA(null, cast(char *)o.toString(), "Error",
> 		    MB_OK | MB_ICONEXCLAMATION);
> 	result = 0;		// failed
>     }
> */
> //    gc_term();			// run finalizers; terminate garbage collector
>     return result;
> }
> 
> extern(Windows)
> {
> 	void DestroyWindow(HANDLE);
> }
> 
> extern(Windows)
> int WndProc(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
> {
> 	switch(uMsg)
> 	{
> 	case WM_DESTROY:
> 		PostQuitMessage(cast(int) null);
> 		break;
> 	case WM_COMMAND:
> 		switch (LOWORD(wParam))
> 		{
> 		case IDM_TEST:
> 			MessageBoxA(cast(HANDLE) null,"Test string","Menu test",MB_OK);
> 		case IDM_HELLO:
> 			MessageBoxA(cast(HANDLE) null,"Hello in D","Menu test",MB_OK);
> 			break;
> 		case IDM_GOODBYE:
> 			MessageBoxA(cast(HANDLE) null,"Goodbye in D","Menu test", MB_OK);
> 			break;
> 		default:
> 			DestroyWindow(hWnd);
> 		}//switch menu selection
> 		break;
> 	default:
> 		return DefWindowProcA(hWnd,uMsg,wParam,lParam);
> 	}//switch msg
> 	return 0;
> }//WndProc()
> 

Hello David

I didn't know how exactly to change the code in order to add the mingw32 lib (-lmingw32), so I tried a different way:

	void main()
	{
	        int exit_code=WinMain(GetModuleHandle(null),null,GetCommandLineA(),SW_SHOWDEFAULT);
	        ExitProcess(exit_code);
	}

	extern (Windows) int WinMain(HINSTANCE hInstance,
	        HINSTANCE hPrevInstance,
	        LPSTR lpCmdLine,
	        int nCmdShow)
	{
	    uint result;
	    result = CMDIApp.MdiWinMain(hInstance, hPrevInstance, lpCmdLine, nCmdShow);
	    return result;
	}


Now I have these errors:

$ ./build-gdc.sh
Compiling resources file (mdiapp.rc)..
Compiling main.d..
Linking to libraries..
main.o:main.d:(.text+0x80): undefined reference to `_D6mdiapp7CMDIApp10MdiWinMainWT5win325winnt6HANDLET5win325winnt6HANDLEPaiZk@16'
main.o:main.d:(.data+0x30): undefined reference to `_D6mdiapp12__ModuleInfoZ'
collect2: ld returned 1 exit status

I'll try to figure out the reason of these errors (any hint?).

Thanks
John



David Friedman wrote:
> Johnny,
> 
> I had the main/WinMain call order backwards.  So, with the current distribution, I do not think it is possible to get the linker to automatically use whichever of main or WinMain is defined (like DMD does(?))
> 
> There is a simple workaround, however:  Use the following command to link.
> 
> gdc -o WinMenu-gdc.exe WinMenu.d -lmingw32
> 
> This will pull in MinGW's C main() that calls WinMain.  The
> 
> Also, you probably want to add -mwindows to the link command line so the .exe will not open a console when run.
> 
> David
> 
> Johnny wrote:
>> David,
>>
>> It's still not working with me; I must have something wrong in my code or in my MinGW/GDC installation.
>>
>> Here is a simple example that I tried to compile with GDC 0.23. I really wish not only to correct the problem, but to understand exactly what's going wrong:
>>
>>
>> Compilation Steps:
>> -----------------
>> 1- $ gdc -c -v WinMenu.d  (OK)
>>
>>     Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
>>     Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc --disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32 --with-gnu-ld --with-gnu-as --enable-threads --disable-nls --disable-win32-registry --disable-shared --enable-sjlj-exceptions
>>     Thread model: win32
>>     gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
>>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet -dumpbase WinMenu.d -auxbase WinMenu -version -iprefix c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s
>>     GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
>>             compiled by GNU C version 3.4.2 (mingw-special).
>>     GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
>>      c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe -o WinMenu.o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccoDaaaa.s
>>
>>
>> 2- $ gdc -v -Wall -o  WinMenu-gdc.exe WinMenu.d -lgphobos  (Link errors)
>>
>>     Reading specs from c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs
>>     Configured with: ../gcc-3.4.5-20060117-1/configure --prefix=/gdc --disable-shared --enable-languages=c,d --host=mingw32 --target=mingw32 --with-gnu-ld --with-gnu-as --enable-threads --disable-nls --disable-win32-registry --disable-shared --enable-sjlj-exceptions
>>     Thread model: win32
>>     gcc version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007)
>>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/cc1d.exe WinMenu.d -quiet -dumpbase WinMenu.d -auxbase WinMenu -Wall -version -iprefix c:\MinGW\bin\../lib/gcc/mingw32/3.4.5/ -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
>>     GNU D version 3.4.5 (mingw special) (gdc 0.23, using dmd 1.007) (mingw32)
>>             compiled by GNU C version 3.4.2 (mingw-special).
>>     GGC heuristics: --param ggc-min-expand=46 --param ggc-min-heapsize=31678
>>      c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/bin/as.exe -o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccQJaaaa.s
>>      c:/MinGW/bin/../libexec/gcc/mingw32/3.4.5/collect2.exe -Bdynamic -o WinMenu-gdc.exe /mingw/lib/crt2.o c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtbegin.o -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5 -Lc:/MinGW/bin/../lib/gcc -L/gdc/lib/gcc/mingw32/3.4.5 -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../mingw32/lib -L/mingw/lib -Lc:/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../.. -L/gdc/lib/gcc/mingw32/3.4.5/../../.. g:\DOCUME~1\ADMINI~1\LOCALS~1\Temp/ccwjbaaa.o -lgphobos -lgphobos -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt -luser32 -lkernel32 -ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt c:/MinGW/bin/../lib/gcc/mingw32/3.4.5/crtend.o
>>     /mingw/lib/libgphobos.a(cmain.o):(.text+0x19): undefined reference to `_Dmain'
>>     collect2: ld returned 1 exit status
>>
>>
>> It seems that the Phobos library itself refers to _Dmain and linker can't find it, so where is _Dmain, and why isn't it found?
>>
>>
>> The source code file is attached.
>>
>> Thanks
>> john
>>
>>
>>
>> David Friedman wrote:
>>> Johnny wrote:
>>>> Hello
>>>>
>>>> I'm trying to make a simple windows GUI application using D.
>>>> First, I used DMD, and I suffered a lot due to it's OMF format. So I decided
>>>> to switch to GDC (with MinGW). But I still receive linking errors related to
>>>> Phobos :-(
>>>>
>>>> Are there any examples or tutorials that can help in this area? I.e. ones
>>>> that show how to set the GC correctly... There are such examples for DMD,
>>>> but I couldn't find similar examples for GDC... So any help?
>>>>
>>>> Thanks
>>>> john
>>>>
>>>>
>>>>
>>>
>>> If you are linking with other libraries, you may need to explicitly link against -lgphobos with that library early on the command line:
>>>
>>> gdc a.o b.o -lgphobos -lwsock32
>>>
>>> If you do not need a custom WinMain, just write the normal D main(). Otherwise, the easiest thing to do is call _d_run_Dmain:
>>>
>>> ---
>>> import std.c.windows.windows;
>>> extern (C) int _d_run_Dmain(int argc, char **argv);
>>> extern (Windows)
>>> int WinMain(HINSTANCE hInstance,
>>>         HINSTANCE hPrevInstance,
>>>         LPSTR lpCmdLine,
>>>         int nCmdShow)
>>> {
>>>     char * fake_argv ="x";
>>>     return _d_run_Dmain(1, & fake_argv);
>>> }
>>>
>>> int main(char[][] args) {
>>>   return 0;
>>> }
>>> ---
>>>
>>> David
>>
>>
>> ------------------------------------------------------------------------
>>
>> import std.c.windows.windows;
>> import std.c.stdio;
>> import std.string;
>>
>> char[] Test_string="You selected Test menu item";
>> char[] Hello_string="Hello, my friend";
>> char[] Goodbye_string="See you again, bye";
>>
>> HINSTANCE hInstance;
>>
>> enum {
>>     IDM_TEST=1,
>>     IDM_HELLO,
>>     IDM_GOODBYE,
>>     IDM_EXIT
>> }
>>
>>
>> int doit() {
>>     hInstance = GetModuleHandleA(null);
>>         WNDCLASS wc;
>>
>>     wc.lpszClassName = "DWndClass";
>>     wc.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
>>     wc.lpfnWndProc = &WndProc;
>>     wc.hInstance = hInstance;
>>     wc.hIcon = LoadIconA(cast(HINSTANCE) null, IDI_APPLICATION);
>>     wc.hCursor = LoadCursorA(cast(HINSTANCE) null, IDC_CROSS);
>>     wc.hbrBackground = cast(HBRUSH) (COLOR_WINDOW + 1);
>>     wc.lpszMenuName = "TestMenu";
>>     wc.cbClsExtra = wc.cbWndExtra = 0;
>>     RegisterClassA(&wc);
>>         HWND hWnd;
>>     char[] sClass="My class 0";
>>     char[] sApp="My Application 0";
>>
>>     /+++++
>>     hWnd = CreateWindowA("DWndClass", "Just a window", WS_THICKFRAME |
>>         WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU | WS_VISIBLE,
>>         CW_USEDEFAULT, CW_USEDEFAULT, 400, 300, HWND_DESKTOP,
>>         cast(HMENU) null, hInstance, null);
>>     +++++/
>>
>>     hWnd = CreateWindowA(toStringz(sClass), toStringz(sApp), WS_THICKFRAME |
>>         WS_MAXIMIZEBOX | WS_MINIMIZEBOX | WS_SYSMENU | WS_VISIBLE,
>>         CW_USEDEFAULT, CW_USEDEFAULT, 400, 300, HWND_DESKTOP,
>>         cast(HMENU) null, hInstance, null);
>>
>>     assert(hWnd);   
>>
>>     ShowWindow(hWnd,SW_SHOWNORMAL);
>>     UpdateWindow(hWnd);
>>
>>     MSG msg;
>>     while (GetMessageA(&msg, cast(HWND) null, 0, 0))
>>     {
>>         TranslateMessage(&msg);
>>         DispatchMessageA(&msg);
>>     }
>>         return 1;
>> }//doit()
>>
>>
>> /**********************************************************/
>>
>> /* Note the similarity of this code to the console D startup
>>  * code in \dmd\src\phobos\dmain2.d
>>  * You'll also need a .def file with at least the following in it:
>>  *    EXETYPE NT
>>  *    SUBSYSTEM WINDOWS
>>  */
>>
>> extern (C) void gc_init();
>> extern (C) void gc_term();
>> extern (C) void _minit();
>> extern (C) void _moduleCtor();
>> extern (C) void _moduleUnitTests();
>>
>> extern (Windows)
>> int WinMain(HINSTANCE hInstance,
>>     HINSTANCE hPrevInstance,
>>     LPSTR lpCmdLine,
>>     int nCmdShow)
>> {
>>     int result;
>>
>> //    gc_init();            // initialize garbage collector
>> //    _minit();            // initialize module constructor table
>>
>> /*    try
>>     {
>>     _moduleCtor();        // call module constructors
>>     _moduleUnitTests();    // run unit tests (optional)
>>
>>     result = doit();    // insert user code here
>>     }
>> */
>> /*    catch (Object o)        // catch any uncaught exceptions
>>     {
>>     MessageBoxA(null, cast(char *)o.toString(), "Error",
>>             MB_OK | MB_ICONEXCLAMATION);
>>     result = 0;        // failed
>>     }
>> */
>> //    gc_term();            // run finalizers; terminate garbage collector
>>     return result;
>> }
>>
>> extern(Windows)
>> {
>>     void DestroyWindow(HANDLE);
>> }
>>
>> extern(Windows)
>> int WndProc(HWND hWnd, uint uMsg, WPARAM wParam, LPARAM lParam)
>> {
>>     switch(uMsg)
>>     {
>>     case WM_DESTROY:
>>         PostQuitMessage(cast(int) null);
>>         break;
>>     case WM_COMMAND:
>>         switch (LOWORD(wParam))
>>         {
>>         case IDM_TEST:
>>             MessageBoxA(cast(HANDLE) null,"Test string","Menu test",MB_OK);
>>         case IDM_HELLO:
>>             MessageBoxA(cast(HANDLE) null,"Hello in D","Menu test",MB_OK);
>>             break;
>>         case IDM_GOODBYE:
>>             MessageBoxA(cast(HANDLE) null,"Goodbye in D","Menu test", MB_OK);
>>             break;
>>         default:
>>             DestroyWindow(hWnd);
>>         }//switch menu selection
>>         break;
>>     default:
>>         return DefWindowProcA(hWnd,uMsg,wParam,lParam);
>>     }//switch msg
>>     return 0;
>> }//WndProc()
>>

Johnny, have you tried the last compile/link command David wrote? I think it will successfully compile/link your application.