The CreateDialogIndirectParam function creates a modeless dialog box from a dialog box template in memory.
lpTemplate [in] Pointer to a global memory object that contains the template CreateDialogIndirectParam uses to create the dialog box. A dialog box template consists of a header that describes the dialog box, followed by one or more additional blocks of data that describe each of the controls in the dialog box. The template can use either the standard format or the extended format. In a standard template, the header is a DLGTEMPLATE structure followed by additional variable-length arrays. The data for each control consists of a DLGITEMTEMPLATE structure followed by additional variable-length arrays.
In an extended dialog box template, the header uses the DLGTEMPLATEEX format and the control definitions use the DLGITEMTEMPLATEEX format.
After CreateDialogIndirectParam returns, you can free the template, which is only used to get the dialog box started.