Как можно с клавы считать дробное число?

acedGetReal Global Function
int acedGetReal(const char * prompt, ads_real * result);
Pauses for user input of a real value, and sets result to the value that the user enters. The prompt argument specifies a string that acedGetReal() displays before it pauses. The prompt is optional; if you don't use it, pass a null pointer instead of a string value. The result argument must point to a memory area large enough to store a double-precision floating-point number.
The AutoCAD user can enter any valid real value, but the user cannot respond to acedGetReal() by entering an AutoLISP expression.
The acedGetReal() function returns one of the following: RTNORM if it succeeds, RTERROR if it fails, or RTCAN if the user cancels the request (by entering [Ctrl]+[C]). A prior call to acedInitGet() can also enable return values of RTNONE or RTKWORD.
Include File
acedads.h