Gets line style from selected CAD data  LTCustomizer21 for AutoCAD LT reference manual

ActiveX
    Function get_select_linestyle(ename As Integer) As String
C/C++
    int WINAPI LTC_get_select_linestyle(int ename,BSTR *linestyle);

parameter
ename :index number read by select(). Specifies a value in range of 0 - return value of select() -1.
linestyle(C/C++ only):line style name

return value
ActiveX:line style name
C/C++: 1:success 0:failure

This function is equal to following code.
get_select_data(ename, 6)