This command adds a DarkBASIC Pro double
float to the specified packet. Typically double floats are 8 bytes in
size and ranges from -1.7E308 to +1.7E308 with 14 to 15 digit accuracy.
The data will be added starting at the cursor position and the cursor will be moved forward by the size of the data added.
long long int Packet: This is the packet that the command should use.
double float: This is the data to be added.
0 if no error occurred.
-1 if an error occurred.
DBP