REFERENCE GUIDE

DialogBoxlndirectReturn valueCommentsIpDialogFuncFARPROC Is the procedure-instance address of the dialogfunction. See the following "Comments" section fordetails.The return value specifies the value of the wResult parameter specified inthe End Dialog function that is used to terminate the dialog box. Valuesreturned by the application's dialog box are processed by Windows andare not returned to the application. The return value is -1 if the functioncould not create the dialog box.A dialog box can contain up to 255 controls.The callback function must use the Pascal calling convention and bedeclared FAR.CallbackFunction BaaL FAR PASCAL DialogFunc(hDlg, wMsg, wParam, IParam)HWNDhDlg;WORDwMsg;WORD wParam;DWORD IParam;DialogFunc is a placeholder for the application-supplied function name.The actual name must be exported by including it in an EXPORTSstatement in the application's module-definition file.Parameters hDlg Identifies the dialog box that receives the message.wMsgwParamIParamSpecifies the message number.Specifies 16 bits of additional message-dependentinformation.Specifies 32 bits of additional message-dependentinformation.Return valueCommentsThe callback function should return nonzero if the function processes themessage and zero if it does not.Although the callback function is similar to a window function, it mustnot call the DefWindowProc function to process unwanted messages.Unwanted messages are processed internally by the dialog-class windowfunction.The callback-function address, passed as the IpDialogFunc parameter, mustbe created by using the MakeProclnstance function.238Software development kit