TBM_GETPAGESIZE  Y.4HUK 

The TBM_GETPAGESIZE message retrieves the size of the page for a trackbar. The page size affects how much the slider moves for the TB_PAGEUP and TB_PAGEDOWN notification messages.

TBM_GETPAGESIZE
wParam = 0;

lParam = 0;

 

Return Values

Returns a 32-bit value that specifies the size of a page for the trackbar.