IntlChar::isdefined — Check whether the code point is defined
Determines whether the specified code point is "defined", which usually means that it is assigned a character.
TRUE for general categories other than "Cn" (other, not assigned).
Note that non-character code points (e.g., U+FDD0) are not "defined" (they are Cn), but surrogate code points are "defined" (Cs).
codepoint is a defined character,
FALSE if not.
Example #1 Testing different code points
The above example will output:
bool(true) bool(true) bool(false)