Convert a string to upper or lower case astChrCase
"
out"
string are used as the input string. "
blen"
. If NULL is supplied for "
in"
, then the supplied
contents of "
out"
are converted and written back into "
out"
over-writing the
supplied contents. "
in"
is NULL. No more than "
blen - 1"
characters will be copied
from "
in"
to "
out"
, and a terminating null character will then be added.