Why some built-in functions "disabled"

Was looking for function “htoa” in 9.50 and couldn’t find it. That is, it wouldn’t compile in and Help couldn’t find it. I searched and found that FUNCTION had an underscore in front of it in the START FUNCTION DESCRIPTION line. Thus, could not be found by Help. I found a bunch of additional functions similarly disabled in STDIO. Anybody know why?

Margaret, a good question for you. :rolleyes: