true, if c forms a valid code point.
assert( isValidCodepoint(cast(char) 0x40)); assert(!isValidCodepoint(cast(char) 0x80)); assert( isValidCodepoint(cast(wchar) 0x1234)); assert(!isValidCodepoint(cast(wchar) 0xD800)); assert( isValidCodepoint(cast(dchar) 0x0010FFFF)); assert(!isValidCodepoint(cast(dchar) 0x12345678));
Checks if a single character forms a valid code point.
When standing alone, some characters are invalid code points. For example the wchar 0xD800 is a so called high surrogate, which can only be interpreted together with a low surrogate following it. As a standalone character it is considered invalid.
See Unicode Standard for more details.