Must be zero.
Returns a DWORD value that contains the previous x-axis distance in the low word, and the previous y-axis distance in the high word.
Values for lParam are relative to the upper-left corner of an icon bitmap. Therefore, to set spacing between icons that do not overlap, the lParam values must include the size of the icon, plus the amount of empty space desired between icons. Values that do not include the width of the icon will result in overlaps.
When defining the icon spacing, the lParam values must set to 4 or larger. Smaller values will not yield the desired layout. To reset the icons to the default spacing, set the lParam values to -1.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|
Build date: 11/16/2013