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red_Marvin · 03-13-2005, 10:18 PM

Some time ago I decided to learn win32API
(or whatever the real name is) for C/C++ and I found a tutorial on the
net that seemed to be on my level.

(that I later gave up because of lack of amition is beside the point -coding apathy )

Now when fB came out I decided to give it a try again, but this time
translating the code in the examples to fB with the help from the
hello.bas win32API example coming with fB.

I have some problems/questions...

1) What is byval? and why do I pass numbers but not strings as byval?
2)why can't I put gszclassname as const in fB It complains about
wrong parameter type ar something like that. Is it about pointers to
string data and the stuff I've seen people have problems with in other threads?
3)Uh. Yeah, also: the code doesn't work (window creation failed) what am i doing wrong?

The C code
[syntax="c"]#include <windows.h>

const char g_szClassName[] = "myWindowClass";

// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;

//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}

// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"The title of my window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);

if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}

ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);

// Step 3: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}[/syntax]

not working fB code...

[syntax="qbasic"]defint a-z
option explicit
option private

'$include once:'win\kernel32.bi'
'$include once:'win\user32.bi'
'$include once:'win\gdi32.bi'

declare function wndproc (byval hwnd as long, _
byval msg as long, _
byval wparam as long, _
byval lparam as long,) as integer

declare function WinMain(byval hinstance as long, _
byval hprevinstance as long, _
lpcmdline as string, _
byval nCmdShow as integer) as integer

end WinMain( GetModuleHandle(0), 0, Command$, SW_NORMAL )

function wndproc (byval hwnd as long, _
byval msg as long, _
byval wparam as long, _
byval lparam as long,) as integer
select case msg
case wm_close: destroywindow(hwnd)
case wm_destroy: postquitmessage 0
case else: wndproc=defwindowproc(hwnd,msg,wparam,lparam)
end select

wndproc=0
end function

function WinMain(byval hinstance as long, _
byval hprevInstance as long, _
lpcommandline as string, _
byval ncmdshow as integer) as integer
dim wc as wndclassex
dim hwnd as long
dim msg as msg
dim gszclassname as string
gszclassname="myWindowClass"
wc.cbsize=len(wndclassex)
wc.style=0
wc.lpfnwndproc=@wndproc
wc.cbclsextra=0
wc.cbwndextra=0
wc.hinstance=hinstance
wc.hicon=loadicon(0,IDI_APPLICATION)
wc.hcursor=loadcursor(0,IDC_ARROW)
wc.hbrbackground=GetStockObject( WHITE_BRUSH )
wc.lpszmenuname=0
wc.lpszclassname=strptr(gszclassname)
wc.hiconsm=loadicon(0,IDI_APPLICATION)

if registerclassex(wc)=0 then
messagebox 0,"window registration failed","error",MB_ICONEXCLAMATION or MB_OK
winmain=0
end 0
else
messagebox 0,"window registration sucsessful","woot",MB_ICONEXCLAMATION or MB_OK
end if

hwnd=createwindowex(WS_EX_CLIENTEDGE ,_
gszclassname ,_
"My window title" ,_
WS_OVERLAPPEDWINDOW ,_
CW_USEDEFAULT ,_
CW_USEDEFAULT ,_
240 ,_
120 ,_
0 ,_
0 ,_
hinstance ,_
0)
if hwnd=0 then
messagebox 0,"window creation failed","error",MB_ICONEXCLAMATION or MB_OK
winmain=0
end 0
end if

showwindow hwnd,ncmdshow
updatewindow hwnd
while getmessage(msg,0,0,0)>0
translatemessage(msg)
dispatchmessage(msg)
wend

winmain=msg.wparam
end function[/syntax] :-? :-? Sad

zydon · 03-13-2005, 11:40 PM

Here is a tips from a newbie:

Move
Code:
wndproc=0
before the Select case in wndproc(..) function. If you delete the line, it still works though.
Add CreateMenu() at 10th parameter for CreateWindowEx API call.
Add brackets into
Code:
if ( hwnd = 0 ) then ...
[/list:o]

And here is the working code:
[syntax="QBasic"]
DEFINT a-z
OPTION explicit
OPTION private

'$include once:'win\kernel32.bi'
'$include once:'win\user32.bi'
'$include once:'win\gdi32.bi'

DECLARE FUNCTION wndproc (BYVAL hwnd AS LONG, _
BYVAL msg AS LONG, _
BYVAL wparam AS LONG, _
BYVAL lparam AS LONG,) AS INTEGER

DECLARE FUNCTION WinMain(BYVAL hinstance AS LONG, _
BYVAL hprevinstance AS LONG, _
lpcmdline AS STRING, _
BYVAL nCmdShow AS INTEGER) AS INTEGER

END WinMain( GetModuleHandle(0), 0, COMMAND$, SW_NORMAL )

FUNCTION wndproc (BYVAL hwnd AS LONG, _
BYVAL msg AS LONG, _
BYVAL wparam AS LONG, _
BYVAL lparam AS LONG,) AS INTEGER
wndproc=0
SELECT CASE msg
CASE wm_close: destroywindow(hwnd)
CASE wm_destroy: postquitmessage 0
CASE ELSE: wndproc=defwindowproc(hwnd,msg,wparam,lparam)
END SELECT

END FUNCTION

FUNCTION WinMain(BYVAL hinstance AS LONG, _
BYVAL hprevInstance AS LONG, _
lpcommandline AS STRING, _
BYVAL ncmdshow AS INTEGER) AS INTEGER
DIM wc AS wndclassex
DIM hwnd AS LONG
DIM msg AS msg
DIM gszclassname AS STRING
gszclassname="myWindowClass"

wc.cbsize=LEN(wndclassex)
wc.style=0
wc.lpfnwndproc=@wndproc
wc.cbclsextra=0
wc.cbwndextra=0
wc.hinstance=hinstance
wc.hicon=loadicon(0,IDI_APPLICATION)
wc.hcursor=loadcursor(0,IDC_ARROW)
wc.hbrbackground=GetStockObject( WHITE_BRUSH )
wc.lpszmenuname=0
wc.lpszclassname=strptr(gszclassname)
wc.hiconsm=loadicon(0,IDI_APPLICATION)

IF registerclassex(wc)=0 THEN
messagebox 0,"window registration failed","error",MB_ICONEXCLAMATION OR MB_OK
winmain=0
END 0
ELSE
messagebox 0,"window registration sucsessful","woot",MB_ICONEXCLAMATION OR MB_OK
END IF

hwnd=createwindowex(WS_EX_CLIENTEDGE ,_
gszclassname ,_
"My window title" ,_
WS_OVERLAPPEDWINDOW ,_
CW_USEDEFAULT ,_
CW_USEDEFAULT ,_
240 ,_
120 ,_
0 ,_
CreateMenu() ,_
hinstance ,_
0)
IF ( hwnd=0 ) THEN
messagebox 0,"window creation failed","error",MB_ICONEXCLAMATION OR MB_OK
winmain=0
END 0
END IF

showwindow(hwnd,ncmdshow)
updatewindow hwnd

WHILE getmessage(msg,0,0,0)>0
translatemessage(msg)
dispatchmessage(msg)
WEND

winmain=msg.wparam
END FUNCTION
[/syntax]

ps - this is kind of weird stuffs that need to completed when using wndclassex in basic compiler. probably, win32 experts can explain why... I am no expert btw...

red_Marvin · 03-14-2005, 12:56 AM

Thanks!
It works now, although I didn't need to put brackets (right word?)
around hwnd=0

Do anyone know why these differences matter in fB compared to c?

adosorken · 03-14-2005, 01:40 AM

Probably because FB is not C, no matter how much some people want it to be.

gbos · 03-14-2005, 03:46 AM

:oops: I have total ignorance about the API and the only thing I managed to do so far is adding a simple button and a simple edit control into a window. Can someone give me an example of how I can read and later change the contents of the edit control by clicking the button??

Also why is only CreateWindowEx Function working and CreateWindow Function doesnât work ?

Code:
DEFINT a-z

OPTION explicit

OPTION private

'$include once:'win\kernel32.bi'

'$include once:'win\user32.bi'

'$include once:'win\gdi32.bi'

    dim shared hInstance as long 

DECLARE FUNCTION wndproc (BYVAL hwnd AS LONG,   _

                          BYVAL msg AS LONG,    _

                          BYVAL wparam AS LONG, _

                          BYVAL lparam AS LONG,) AS INTEGER

DECLARE FUNCTION WinMain(BYVAL hinstance AS LONG,     _

                         BYVAL hprevinstance AS LONG, _

                               lpcmdline AS STRING,   _

                         BYVAL nCmdShow AS INTEGER) AS INTEGER

END WinMain( GetModuleHandle(0), 0, COMMAND$, SW_NORMAL )

FUNCTION wndproc (BYVAL hwnd AS LONG,   _

                  BYVAL msg AS LONG,    _

                  BYVAL wparam AS LONG, _

                  BYVAL lparam AS LONG,) AS INTEGER

   wndproc=0

   SELECT CASE msg

   Case WM_CREATE

         DIM bclassname AS STRING

         DIM eclassname AS STRING

         bclassname="BUTTON"

         eclassname="EDIT"

         Dim hwndButton as long

         Dim hwndEdit as long

         hwndButton = createwindowex(WS_EX_LEFT,bclassname,"Hello",WS_VISIBLE or WS_CHILD or BS_DEFPUSHBUTTON,10,10,50,100,hwnd,null,hInstance,null)

         hwndEdit = createwindowex(WS_EX_DLGMODALFRAME,eclassname,"555",WS_CHILD or WS_VISIBLE or WS_VSCROLL or ES_LEFT or ES_MULTILINE or ES_AUTOVSCROLL,70,10,150,100,hwnd,null,hInstance,null)

         'SendMessage(hwndEdit, WM_SETTEXT, 0, lparam) 

      CASE wm_close: destroywindow(hwnd)

      CASE wm_destroy: postquitmessage 0

      CASE ELSE: wndproc=defwindowproc(hwnd,msg,wparam,lparam)

   END SELECT

END FUNCTION

FUNCTION WinMain(BYVAL hinstance AS LONG,       _

                 BYVAL hprevInstance AS LONG,   _

                       lpcommandline AS STRING, _

                 BYVAL ncmdshow AS INTEGER) AS INTEGER

   DIM wc AS wndclassex

   DIM hwnd AS LONG

   DIM msg AS msg

   DIM gszclassname AS STRING

       gszclassname="myWindowClass"

   wc.cbsize=LEN(wndclassex)

   wc.style=0

   wc.lpfnwndproc=@wndproc

   wc.cbclsextra=0

   wc.cbwndextra=0

   wc.hinstance=hinstance

   wc.hicon=loadicon(0,IDI_APPLICATION)

   wc.hcursor=loadcursor(0,IDC_ARROW)

   wc.hbrbackground=GetStockObject( WHITE_BRUSH )

   wc.lpszmenuname=0

   wc.lpszclassname=strptr(gszclassname)

   wc.hiconsm=loadicon(0,IDI_APPLICATION)

   IF registerclassex(wc)=0 THEN

      messagebox 0,"window registration failed","error",MB_ICONEXCLAMATION OR MB_OK

      winmain=0

      END 0

   ELSE

      messagebox 0,"window registration sucsessful","woot",MB_ICONEXCLAMATION OR MB_OK     

   END IF

   hwnd=createwindowex(WS_EX_CLIENTEDGE    ,_

                       gszclassname        ,_

                       "My window title"   ,_

                       WS_OVERLAPPEDWINDOW ,_

                       CW_USEDEFAULT       ,_

                       CW_USEDEFAULT       ,_

                       300                 ,_

                       200                 ,_

                       0                   ,_

                       CreateMenu()        ,_

                       hinstance           ,_

                       0)

   IF ( hwnd=0 ) THEN

      messagebox 0,"window creation failed","error",MB_ICONEXCLAMATION OR MB_OK

      winmain=0

      END 0

   END IF

   showwindow(hwnd,ncmdshow)

   updatewindow hwnd

   WHILE getmessage(msg,0,0,0)>0

      translatemessage(msg)

      dispatchmessage(msg)

   WEND

   winmain=msg.wparam

END FUNCTION

Sisophon2001 · 03-14-2005, 10:02 AM

Quote:Thanks!
It works now, although I didn't need to put brackets (right word?)
around hwnd=0

Do anyone know why these differences matter in fB compared to c?

Hi:

I am another newbie using FreeBASIC for the first time, and but then FreeBASIC is new, so I guess we are all learning together.

I did not try your code, as zydon already got it working for you, but I will try answering your questions based on what I have see and read so far.

1)
A variable in FreeBASIC has a value and a memory address where that value is stored. If you send a variable to a Win API function BYVAL, you are sending its value. If you send a variable BYREF, you are sending the address. There is an exception to this simple rule. In C which all the windows API was written in, a string is an array of characters. In FreeBASIC it is a structure, containing the string of characters, the string length and the string type (and possibly some more info that I donât recall). If a Windows API function expects the address of an array of characters, you can not send it the address of a BASIC string, or you will crash. Instead there is a convention that you send the string BYVAL, and the FreeBASIC compiler understands that what you actually want is to send a reference to the actual data inside the string.

2)
const char g_szClassName[] = "myWindowClass";

g_szClassName is a character pointer, not a constant like used in FreeBASIC. The prefix const is to tell the C++ compiler (and this is C++ code, not C code) not to allow the programmer to edit the string. Depending on how you tried to translate this into BASIC you might have mixed things up. A CONST in FreeBASIC behaves like a #define in C.

3)
wndproc=0

In FreeBASIC giving a value to the function return does not cause the function to exit. You need to add EXIT FUNCTION, or do as Zydon recommended, and move the wndproc=0 to before the select case. The problem with the original code was that

wndproc=defwindowproc(hwnd,msg,wparam,lparam)

just assigned a value to wndproc, but this value was never returned from the function because the function did not exit at that point. It was overwritten by wndproc=0 you had at the bottom of the function.

Have fun

Garvan

Sisophon2001 · 03-14-2005, 10:56 AM

Quote::

Can someone give me an example of how I can read and later change the contents of the edit control by clicking the button??

Also why is only CreateWindowEx Function working and CreateWindow Function doesnât work ?

Hi:

The code below should help you on your way. Sorry about reformatting it, I have a habit of using all uppercase Keywords, and the code looked ugly with a mixture of different styles.

CreateWindowEx() is defined in the headerfiles, CreateWindow() is not.

In MinGW CreateWindow() is a macro that calls CreateWindowEx(). I used a similar macro in the code below just for testing.

Garvan

Code:
DEFINT a-z

OPTION explicit

OPTION PRIVATE

'$include once:'win\kernel32.bi'

'$include once:'win\user32.bi'

'$include once:'win\gdi32.bi'

CONST IDC_BUTTON1 = 2001

DIM SHARED hInstance AS long

DIM SHARED hwndButton AS long

DIM SHARED hwndEdit AS long

#DEFINE CreateWindow(a,b,c,d,e,f,g,h,i,j,k) CreateWindowEx(0,a,b,c,d,e,f,g,h,i,j,k)

DECLARE FUNCTION wndproc (BYVAL hwnd AS LONG,   _

                          BYVAL msg AS LONG,    _

                          BYVAL wparam AS LONG, _

                          BYVAL lparam AS LONG,) AS INTEGER

DECLARE FUNCTION WinMain(BYVAL hinstance AS LONG,     _

                         BYVAL hprevinstance AS LONG, _

                         lpcmdline AS STRING,   _

                         BYVAL nCmdShow AS INTEGER) AS INTEGER

END WinMain( GetModuleHandle(0), 0, COMMAND$, SW_NORMAL )

FUNCTION wndproc (BYVAL hwnd AS LONG,   _

                  BYVAL msg AS LONG,    _

                  BYVAL wparam AS LONG, _

                  BYVAL lparam AS LONG,) AS INTEGER

  wndproc=0

  SELECT CASE msg

  CASE WM_COMMAND

    SELECT CASE LOWORD(wParam)

    CASE IDC_BUTTON1

      IF HIWORD(wParam) = BN_CLICKED THEN

        DIM fn AS STRING * 300  'Use a fixed length string bigger then the max size

        DIM text_len AS LONG

        text_len = GetWindowText(hwndEdit,fn, 256) 'request 256 characters max size

        IF text_len <> 0 THEN MessageBox 0,fn,"woot",MB_ICONEXCLAMATION OR MB_OK

      END IF

    END SELECT

  CASE WM_CREATE

    DIM bclassname AS STRING

    DIM eclassname AS STRING

    bclassname="BUTTON"

    eclassname="EDIT"

    hwndButton = createwindow(bclassname,"Hello",WS_VISIBLE OR WS_CHILD OR BS_DEFPUSHBUTTON,10,10,50,100,hwnd,IDC_BUTTON1,hInstance,null)

    hwndEdit = createwindow(eclassname,"555",WS_CHILD OR WS_VISIBLE OR WS_VSCROLL OR ES_LEFT OR ES_MULTILINE OR ES_AUTOVSCROLL,70,10,150,100,hwnd,null,hInstance,null)

    DIM s AS STRING

    s = "Some text"

    SendMessage(hwndEdit, WM_SETTEXT, 0, BYVAL s)

    'You can also use SetWindowText

    'SetWindowText(hwndEdit,s)

  CASE wm_close: destroywindow(hwnd)

  CASE wm_destroy: postquitmessage 0

  CASE ELSE: wndproc=defwindowproc(hwnd,msg,wparam,lparam)

  END SELECT

END FUNCTION

FUNCTION WinMain(BYVAL hinstance AS LONG,       _

                 BYVAL hprevInstance AS LONG,   _

                 lpcommandline AS STRING, _

                 BYVAL ncmdshow AS INTEGER) AS INTEGER

  DIM wc AS wndclassex

  DIM hwnd AS LONG

  DIM msg AS msg

  DIM gszclassname AS STRING

  gszclassname="myWindowClass"

  wc.cbsize=LEN(wndclassex)

  wc.style=0

  wc.lpfnwndproc=@wndproc

  wc.cbclsextra=0

  wc.cbwndextra=0

  wc.hinstance=hinstance

  wc.hicon=loadicon(0,IDI_APPLICATION)

  wc.hcursor=loadcursor(0,IDC_ARROW)

  wc.hbrbackground=GetStockObject( WHITE_BRUSH )

  wc.lpszmenuname=0

  wc.lpszclassname=STRPTR(gszclassname)

  wc.hiconsm=loadicon(0,IDI_APPLICATION)

  IF registerclassex(wc)=0 THEN

    messagebox 0,"window registration failed","error",MB_ICONEXCLAMATION OR MB_OK

    winmain=0

    END 0

  ELSE

    messagebox 0,"window registration sucsessful","woot",MB_ICONEXCLAMATION OR MB_OK

  END IF

  hwnd = createwindow(gszclassname        ,_

                      "My window title"   ,_

                      WS_OVERLAPPEDWINDOW ,_

                      CW_USEDEFAULT       ,_

                      CW_USEDEFAULT       ,_

                      300                 ,_

                      200                 ,_

                      0                   ,_

                      CreateMenu()        ,_

                      hinstance           ,_

                      0)

  IF ( hwnd=0 ) THEN

    messagebox 0,"window creation failed","error",MB_ICONEXCLAMATION OR MB_OK

    winmain=0

    EXIT FUNCTION

  END IF

  showwindow(hwnd,ncmdshow)

  updatewindow hwnd

  WHILE getmessage(msg,0,0,0)>0

    translatemessage(msg)

    dispatchmessage(msg)

  WEND

  winmain=msg.wparam

END FUNCTION

gbos · 03-14-2005, 02:01 PM

8) Thanks!!

v3cz0r · 03-14-2005, 09:00 PM

Yeah, CreateWindow is actually a macro in C, it isn't part of the Win API, only CreateWindowEx.

()'s used with compound statements only make them more clear, there's no difference in the generated code.

red_Marvin · 03-16-2005, 07:53 PM

isn't dialogbox() supported by fB? or is it also a macro?

[syntax="c"]int ret = DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(IDD_ABOUT), hwnd, AboutDlgProc);[/syntax]

[syntax="qbasic"]dim ret as integer
ret=dialogbox(getmodulehandle(0), IDD_ABOUT, hwnd, aboutdialogproc)[/syntax]

The fB code gives me "error 42, Variable not declared, found 'dialogbox'"
Is dialogbox also just a macro? if so could someone point me to how I
should translate it to whatever I should translate it to.

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