Hi Todd, I am curious, what was the problem? I tried 0 in the first place and the script died. Though it has something to do with the 0 but obviously it has not.
On Sun, 29 Dec 2019 at 10:31, ToddAndMargo via perl6-users < perl6-users@perl.org> wrote: > On 2019-12-29 00:28, ToddAndMargo via perl6-users wrote: > >>> On Fri, Dec 27, 2019 at 6:06 AM ToddAndMargo via perl6-users > >>> <perl6-users@perl.org <mailto:perl6-users@perl.org>> wrote: > >>> > >>> Hi All, > >>> > >>> https://docs.perl6.org/language/nativecall > >>> > >>> "As you may have predicted by now, a NULL pointer > >>> is represented by the type object of the struct type." > >>> > >>> > >>> > https://docs.microsoft.com/en-us/windows/win32/api/winreg/nf-winreg-regqueryvalueexw > >>> > >>> > >>> C++ > >>> LSTATUS RegQueryValueExW( > >>> HKEY hKey, > >>> LPCWSTR lpValueName, > >>> LPDWORD lpReserved, > >>> LPDWORD lpType, > >>> LPBYTE lpData, > >>> LPDWORD lpcbData > >>> ); > >>> > >>> lpReserved > >>> This parameter is reserved and must be NULL. > >>> > >>> With "native", how do I satisfy the "NULL" requirement? > >>> > >>> constant WCHAR := uint16; > >>> > >>> constant DWORD := int32; > >>> > >>> > >>> sub RegQueryValueExW( DWORD, WCHARS, DWORD, DWORD, DWORD is rw, > >>> DWORD is > >>> rw ) is native("Kernel32.dll") returns DWORD { * }; > >>> > >>> $RtnCode = RegQueryValueExW( $Handle, $lpValueName, int32, > >>> REG_DWORD, > >>> $lpData, $lpcbData ); > >>> > >>> "int32" returns: > >>> > >>> Cannot unbox a type object (int32) to int in method > >>> CALL-ME at C:\rakudo\share\perl6\sources > >>> \947BDAB9F96E0E5FCCB383124F9 > >>> 23A6BF6F8D76B (NativeCall) line 587 > >>> > >>> > >>> Many thanks, > >>> -T > >>> > > > > On 2019-12-27 06:10, Brad Gilbert wrote: > >> A Null pointer is just a pointer that points to the address 0. > >> > >> So if you are dealing with it as an integer it will be 0. > > Hi Brad, > > Disregard my last post. I found a booboo somewhere else. > You were correct about the zero. > > Thank you! > > -T >
