Second instance of program -> cause change in first instance

[lee321987]

Hello. I have a script that I won't only one instance to run, but when a second instance is attempted, it causes a variable to change in the first instance. Possible?

[Melba23]

lee321987,

Yes......but (there is always a but!) what sort of variable? Number, string?

Compile this script and run it twice. The first instance receives a string from the second, which then exits.

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#Region ;**** Directives created by AutoIt3Wrapper_GUI ****
#AutoIt3Wrapper_UseUpx=n
#EndRegion ;**** Directives created by AutoIt3Wrapper_GUI ****

; Based on code from Yashied

#include <GUIConstantsEx.au3>

Opt("WinTitleMatchMode", 3)

Global Const $WM_COPYDATA = 0x004A
Global $hLabel, $sMsg_Rcvd, $sMsg_Set = ""

; Set GUI title
If WinExists("First Instance") Then
    $hWnd = WinGetHandle("First Instance")
    If (Not @error) Then _SendData($hWnd, "Hi from Second Instance")
    Sleep(1000)
    Exit
EndIf

; Create GUI
GUICreate("First Instance", 200, 100)

$hLabel = GUICtrlCreateLabel("", 10, 10, 180, 20)

GUISetState()

GUIRegisterMsg($WM_COPYDATA, "_WM_COPYDATA")

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
    EndSwitch

    ; Check messages received
    If $sMsg_Rcvd <> $sMsg_Set Then
    GUICtrlSetData($hLabel, $sMsg_Rcvd)
    $sMsg_Set = $sMsg_Rcvd
    EndIf

WEnd

Func _SendData($hWnd, $sData)

    Local $tCOPYDATA, $tMsg

    $tMsg = DllStructCreate("char[" & StringLen($sData) + 1 & "]")
    DllStructSetData($tMsg, 1, $sData)
    $tCOPYDATA = DllStructCreate("dword;dword;ptr")
    DllStructSetData($tCOPYDATA, 2, StringLen($sData) + 1)
    DllStructSetData($tCOPYDATA, 3, DllStructGetPtr($tMsg))
    $Ret = DllCall("user32.dll", "lparam", "SendMessage", "hwnd", $hWnd, "int", $WM_COPYDATA, "wparam", 0, "lparam", DllStructGetPtr($tCOPYDATA))
    If (@error) Or ($Ret[0] = -1) Then Return 0
    Return 1

EndFunc   ;==>_SendData

Func _WM_COPYDATA($hWnd, $msgID, $wParam, $lParam)

    Local $tCOPYDATA = DllStructCreate("dword;dword;ptr", $lParam)
    Local $tMsg = DllStructCreate("char[" & DllStructGetData($tCOPYDATA, 2) & "]", DllStructGetData($tCOPYDATA, 3))
    $sMsg_Rcvd = DllStructGetData($tMsg, 1)
    Return 0

EndFunc   ;==>_WM_COPYDATA

Sending a number is even easier!

M23

Edit: Added script.

Edited December 22, 2009 by Melba23

[lee321987]

I must apologize - I worded my first post poorly. The second instance doesn't need to pass any data, I just need the first instance to be aware that a second instance was attempted (then a timer will reset).

However I'm grateful that you posted what you did, because I'm sure I will use it, and I'm interested in passing numbers too if you want to elaborate.

[Melba23]

lee321987,

I do not think your first post was worded poorly at all - you have to send a message somehow!

Here is the "number" version - again compile and run twice:

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#Region ;**** Directives created by AutoIt3Wrapper_GUI ****
#AutoIt3Wrapper_UseUpx=n
#EndRegion ;**** Directives created by AutoIt3Wrapper_GUI ****

; Based on code from Yashied

#include <GUIConstantsEx.au3>
#include <WinApi.au3>

Opt("WinTitleMatchMode", 3)

Global Const $WM_MYMSG = _WinAPI_RegisterWindowMessage('WM_MYMSG')
Global Const $HWND_BROADCAST = 0xFFFF

Global $iValue_Rcvd = Default

; Set GUI title
If WinExists("First Instance") Then
    $hGUI2 = GUICreate("", 1, 1, 0, 0)
    GUISetState()
    _WinAPI_PostMessage($HWND_BROADCAST, $WM_MYMSG, 999999, $hGUI2)
    GUIDelete($hGUI2)
    Exit
EndIf

; Create GUI
$hGUI = GUICreate("First Instance", 200, 100)

$hLabel = GUICtrlCreateLabel("", 10, 10, 180, 20)

GUISetState()

GUIRegisterMsg($WM_MYMSG, 'WM_MYMSG')

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
    EndSwitch

    ; Check messages received
    If $iValue_Rcvd <> Default Then
        GUICtrlSetData($hLabel, Number($iValue_Rcvd))
        $iValue_Set = Default
    EndIf

WEnd

Func WM_MYMSG($hWnd, $iMsg, $wParam, $lParam)
    ; Only react if sent from another GUI
    If $lParam <> $hGUI Then $iValue_Rcvd = $wParam
EndFunc   ;==>WM_MYMSG

If all you want is to know if the second instance has been attempted, this is the easier code as you can see.

M23

P.S. And in case you did not notice, you can thank Yashied for these scripts - I am nowhere near clever enough.