Using updated NSIS path within the same installer

I am having a problem with updating the PATH variable. What I need to do is update the path (which works fine), and then immediately use the new version in the installer. This is not working.

H开发者_JAVA技巧ere is what I'm using to update the path:

!macro ADD_TO_PATH pathAdd
       DetailPrint "Adding ${pathAdd} to the system PATH."
       ReadRegStr $1 ${WriteEnvStr_RegKey} "PATH"
       WriteRegStr ${WriteEnvStr_RegKey} "PATH" "$1;${pathAdd}"
       SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000

       ReadRegStr $1 ${WriteEnvStr_RegKey} "PATH"
       MessageBox MB_OK "Path: $1"

!macroend

And here is what I need to do with it:

Section "${PRODUCT_NAME}" SEC_R

        DetailPrint 'Installing Python Dateutil...'
        !insertmacro EXEC_OUT 'dtutil' 'easy_install python-dateutil' 'DateUtil' 'true'

SectionEnd

Where EXEC_OUT is the following:

; Silent execution of easy_install.
; abrt    - is set to 'true', causes Abort on failure.
; name    - user-friendly name to print
; package - unique name for labels
; what    - full command to execute(ex: "easy_install packageXYZ")
!macro EXEC_OUT package what name abrt

       MessageBox MB_OK "what: ${what}"
       ExecWait "${what}" $0
       ${If} $0 == "0"
             DetailPrint "${name} module installed successfully."
       ${Else}
              DetailPrint "${name} failed to install: $0"
             ${If} ${abrt} == "true"
                  abort "An essential part of the installation, ${name}, failed to install. Aborting installation."
             ${EndIf}
       ${EndIf}

!macroend

Why is this not working? Is it not possible for the PATH to be updated before the application exits?

---

You need to set the environment variable for the running process as well.

http://nsis.sourceforge.net/Setting_Environment_Variables_to_Active_Installer_Process