Querying control data

To get at once all the data describing the current state of the control via the SPLITCTLDATA structure you must use the WM_QUERYWINDOWPARAMS PM message as described in the code snippet below.
WNDPARAMS wp; SPLITCTLDATA scd; memset(&scd, 0, sizeof(scd)); scd.cb = sizeof(scd); memset(&wp, 0, sizeof(wp)); wp.fsStatus = WPM_CBCTLDATA | WPM_CTLDATA; wp.cbCtlData = scd.cb; wp.pCtlData = &scd; // get the control data if (WinSendMsg(g.hwndSplitPane, WM_QUERYWINDOWPARAMS, (MPARAM)&wp, MPVOID)) { ... }