What does the % symbol mean when used in the BASIC computer language?
This is an example:
DECLARE SUB SendBlock (Code%)
What does Code% mean in this context?

I used basic a lot many moons ago ...

I believe the answer to your question is one of the following:

1. it is an abbreviation for integer
2. it is passed by reference (if you change the value in the sub it
changes the passed parameter)

This is easy to test

for 1. pass the number 1.234 and msgbox it to the screen from within
the SendBlock sub (I feel pretty sure about this one)
for 2. pass the numner 1 and inside the funtion assign 2 to the
variable.  msgbox the result to the screen from the calling function
e.g. x=1: SendBlock(x)): msgbox str(x)

Let me know what you find pls.

Good luck.