On 06/26/14 06:05, Shuai Meng wrote:

Hi,
I notice that Abs(Null) should return Null according to
http://msdn.microsoft.com/en-us/library/307330xe(v=vs.84).aspx

In wine source code, NULL is defined as 0 in
file dlls/windowscodecs/ungif.h, line 66. I have tried to write like this:
1260 ������ ������ if(V_VT(arg) == VT_NULL) {
1261 ������ ������ ������ ������ V_VT(res) = VT_NULL;
1262 ������ ������ ������ ������ V_NULL(res) = NULL;
1263 ������ ������ }

In case of VT_NULL variant type there's no need to set variant value. You only need to set V_VT(res) to VT_NULL.

You also need to handle res==NULL case here.