what is DDE?

i'm new to using IB. i noticed a lot of people that use them talk about DDE. what is it and what are some common usages?

thanks

 

DDE = Dynamic Data Exchange allows information to be shared or communicated between programs. It is a interprocess communication (IPC) that uses shared memory as a common exchange area and provides applications with a protocol or set of commands and message formats. It basically uses a client/server model in which the application requesting data is considered the client and the application providing data is considered the server.

WRITING DATA TO EXCEL:
/* The DDE link is established using */
/* Microsoft Excel SHEET1, rows 1 */
/* through 100 and columns 1 through 3 */
filename random dde
'excel|sheet1!r1c1:r100c3';
data random;
file random;
do i=1 to 100;
x=ranuni(i);
y=10+x;
z=x-10;
put x y z;
end;
run;

READING DATA TO EXCEL:
/* The DDE link is established using */
/* Microsoft Excel SHEET1, rows 1 */
/* through 10 and columns 1 through 3 */
filename monthly
dde 'excel|sheet1!r1c1:r10c3';
data monthly;
infile monthly;
input var1 var2 var3;
run;
proc print;
run;