std::ctype::scan_is,std::ctype::do_scan_is (3) Linux Manual Page

std::ctype<CharT>::scan_is,std::ctype<CharT>::do_scan_is – std::ctype<CharT>::scan_is,std::ctype<CharT>::do_scan_is

Synopsis

Defined in header<locale>

    public : (1)

                 const CharT *scan_is(mask m, const CharT *beg, const CharT *end) const;

protected:
(2)

    virtual const CharT *do_scan_is(mask m, const CharT *beg, const CharT *end) const;

1) public member function, calls the protected virtual member function do_scan_is of the most derived class.
2) Locates the first character in the character array [beg, end) that satisfies the classification mask m, that is, the first character c such that is(m, c) would return true.

Parameters

m – mask to search for
beg – pointer to the first character in an array of characters to search
end – one past the end pointer for the array of characters to search

Return value

Pointer to the first character in [beg, end) that satisfies the mask, or end if no such character was found.

Example

// Run this code

#include <locale>

#include <clocale>

#include <iostream>

#include <iterator>
int main()

{
    std::setlocale(LC_ALL, "en_US.utf8");
    std::wcout.imbue(std::locale("en_US.utf8"));
    auto &f = std::use_facet<std::ctype<wchar_t>>(std::wcout.getloc());
    // skip until the first letter
    wchar_t s1[] = L"      \t\t\n  Кошка";
    const wchar_t *p1 = f.scan_is(std::ctype_base::alpha, std::begin(s1), std::end(s1));
    std::wcout << "'" << p1 << "'\n";
    // skip until the first letter
    wchar_t s2[] = L"123456789ネプネプ";
    const wchar_t *p2 = f.scan_is(std::ctype_base::alpha, std::begin(s2), std::end(s2));
    std::wcout << "'" << p2 << "'\n";
}

Output:

  ‘Кошка’
  ‘ネプネプ’

See also

            locates the first character in a sequence that conforms to given classification, using the classification table
scan_is (public member function of std::ctype<char>)
do_scan_not locates the first character in a sequence that fails given classification
            (virtual protected member function)
[virtual]