A virtual function called to locate the first character in a range that matches a specified mask.
virtual const CharType *do_scan_is(
const CharType* first,
const CharType* last,
The mask value to be matched by a character.
A pointer to the first character in the range to be scanned.
A pointer to the character immediately following the last character in the range to be scanned.
A pointer to the first character in a range that does match a specified mask. If no such value exists, the function returns last.
The protected member function returns the smallest pointer ptr in the range [first, last) for which do_is(maskVal, *ptr) is true.
See the example for scan_is, which calls do_scan_is.