How to make a volatile registry using NSIS script

There is no native way to make a volatile registry key in NSIS, so we have to call WINAPI directly.

!define REG_OPTION_VOLATILE             1 Function MakeVolatileKey     System::Call 'advapi32::RegCreateKeyEx(i ${HKEY_LOCAL_MACHINE}, t "Software\volatile", i0, i0, i ${REG_OPTION_VOLATILE}, i ${GENERIC_WRITE}, i0, *i.r1, *i)i.r0'     ${If} $0 = 0             System::Call 'advapi32::RegCloseKey(ir1)'             WriteRegDWORD HKLM "Software\volatile" test 1     ${EndIf}   FunctionEnd

But, there is one thing we have to consider on 64bit Windows.
If we add a code 'SetRegView 64' in order to avoid registry redirection, two registry keys are made:
    1. HKEY_LOCAL_MACHINE\SOFTWARE\Volatile (by WriteRegDWORD)
    2, HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\volatile (by RegCreateKeyEx)
 
SetRegView can not affect native registry APIs; then we should apply a KEY_WOW64_64KEY option to RegCreateKeyEx API.

!include WinCore.nsh !include LogicLib.nsh !include x64.nsh !define REG_OPTION_VOLATILE             1 !define KEY_WOW64_64KEY                 0x0100 Function MakeVolatileKey     ${If} ${RunningX64}         IntOp $R0 ${GENERIC_WRITE} + ${KEY_WOW64_64KEY}         SetRegView 64     ${Else}         Strcpy $R0 ${GENERIC_WRITE}                SetRegView 32     ${EndIf}       System::Call 'advapi32::RegCreateKeyEx(i ${HKEY_LOCAL_MACHINE}, t "Software\volatile", i0, i0, i ${REG_OPTION_VOLATILE}, i $R0, i0, *i.r1, *i)i.r0'     ${If} $0 = 0             System::Call 'advapi32::RegCloseKey(ir1)'             WriteRegDWORD HKLM "Software\Volatile" test 1     ${EndIf}   FunctionEnd