ampersand used in SET /A command in Windows batch script

Question

Could you please advice what using "&" or "^" in SET command means (I haven't found any explanation by using Google).

For example, following Windows batch code block

SET V_COMMAND=3
SET /A V_FLAG="%V_COMMAND%&2"
echo VFlag is: %V_FLAG%

produces:

VFlag is: 2

But I haven't any opinion about what command above does.

Also there is another case with " ^ ":

SET V_COMMAND=3
SET /A V_FLAG="%V_COMMAND%^3"
echo VFlag is: %V_FLAG%

For this case output is:

VFlag is: 0

Answer 1

Since you are using set /a , the indicated characters are bitwise operators:

& = bitwise AND = 1 if both bits are 1
^ = bitwise XOR = 1 if only one of the two bits is 1

So if a is 10 ( 1010 in binary) and b is 13 ( 1101 in binary)

         1010              1010
         1101              1101
         ----              ----
         1000 = a & b      0111 = a ^ b

Or in your case with 3 dec = 11 bin and 2 dec = 10 bin

           11                11
           10                11
           --                --
           10 = 3&2 = 2      00 = 3^3 = 0

Answer 2

Those are bitwise operators - & is bitwise AND, and ^ is bitwise XOR. These bitwise operators are only available with SET /A .