std::ctype<char>::scan_is

Header: <locale>

Locates the first character in the character array [beg,end) that satisfies the classification mask m, that is, the first character c such that table()[(unsigned char) c] & m would return true.

# Declarations

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

# 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.

# Notes

Unlike the primary template std::ctype, this specialization does not perform a virtual function call when classifying characters. To customize the behavior, a derived class may provide a non-default classification table to the base class constructor.

# Example

#include <iostream>
#include <iterator>
#include <locale>
 
int main()
{
    std::locale loc("");
    auto& f = std::use_facet<std::ctype<char>>(loc);
 
    // skip until the first letter
    char s1[] = "      \t\t\n  Test";
    const char* p1 = f.scan_is(std::ctype_base::alpha, std::begin(s1), std::end(s1));
    std::cout << '\'' << p1 << "'\n";
 
    // skip until the first letter
    char s2[] = "123456789abcd";
    const char* p2 = f.scan_is(std::ctype_base::alpha, std::begin(s2), std::end(s2));
    std::cout << '\'' << p2 << "'\n";
}