in the global includes add this:

Module('Windows API')
  FindWindow(*LPCSTR,*LPCSTR),HWND,PASCAL,RAW,NAME('FindWindowA')
End

in the data add this :

FindWindowName CSTIRNG(50)
FindWindowHandle Unsigned

in the global embed program setup add this :

FindWindowName = 'Window title'

FindWindowHandle = FindWindow(,FindWindowName)
IF FindWindowHandle
    MESSAGE('You cannot run more than one instance of ' & FindWindowName)
    return
END

Thanks for replying But I have a query
when I try to do the following

in the global includes add this:

Module('Windows API')
  FindWindow(*LPCSTR,*LPCSTR),HWND,PASCAL,RAW,NAME('FindWindowA')
End

I get the following error
illegal return type or attribute

I was not sure where to put the above line so i put it in the global map as i couldnt find  the global includes only before or after global includes.

I'm using c5.5 and its full upto date with the patches.

Any ideas?

Many thanks
JJ

ooops,
sorry my fault !
you also have to declare LPCSTR LPSTR and HWND

LPSTR                   EQUATE(CSTRING)
LPCSTR                  EQUATE(CSTRING)   
HANDLE                  EQUATE(UNSIGNED)
HWND                    EQUATE(HANDLE)

put that somewhere after the global includes.

Hi
Thanks for the quick reply

Ive added those but now its giving this error
Parameter cannot be ommited
at this line
FindWindowHandle = FindWindow(,FindWindowName)

Many thanks again
JJ

try this prototype for findwindow:

Module('winapi')
 FindWindow(<*cstring>,*cstring),unsigned,pascal,raw,name('FindWindowA')
End

The first parameter is the name of the class, for a clarion application it will be something like ClaWin and a lot of figures... ie Clawin8388608Class1
The second parameter is the title of the window (in the title bar.)

if you pass a NULL to the calss name then windows then this api will look through all the classes.. otherwise it will search everywhere.

If it still does not work then try this other method, it loop through all the opened windows (visible or not) until it finds a clarion program, then checks that it is the one you are interrested in.

module('winapi')
  GetClassName(UNSIGNED,*CSTRING,SIGNED),SIGNED,PASCAL,RAW,NAME('GetClassNameA')
  GetWindowText(Long,Long,SIGNED),SIGNED,PASCAL,RAW,NAME('GetWindowTextA')
End

WindowHandle USHORT
WindowTitle  CSTRING(256)
ClassName    CSTRING(256)

FindWindowName = 'The title of of the window to close'

Loop WindowHandle = 1 To 0FFFFh
    rlen# = GetWindowText(WindowHandle,Address(WindowTitle),200)
    If rlen# Then
        ret#  = GetClassName(WindowHandle,ClassName,200)
        If (Sub(ClassName,1,6) = 'ClaWin') And Clip(WindowTitle) = FindWindowName)  Then
             MESSAGE('You cannot run more than one instance of ' & FindWindowName)
             Return
         End
    End
End

Many Thanks
After playing around with your code I've got it working
Thank you for all your help
JJ