std::strcoll(3)

NAME
std::strcoll - std::strcoll

Synopsis
   Defined in header <cstring>
   int strcoll( const char* lhs, const char* rhs );
   Compares two null-terminated byte strings according to the current locale as defined
   by the LC_COLLATE category.

Parameters
   lhs, rhs - pointers to the null-terminated byte strings to compare

Return value
     * Negative value if lhs is less than (precedes) rhs.
     * 0 if lhs is equal to rhs.
     * Positive value if lhs is greater than (follows) rhs.

Notes
   Collation order is the dictionary order: the position of the letter in the national
   alphabet (its equivalence class) has higher priority than its case or variant.
   Within an equivalence class, lowercase characters collate before their uppercase
   equivalents and locale-specific order may apply to the characters with diacritics.
   In some locales, groups of characters compare as single collation units. For
   example, "ch" in Czech follows "h" and precedes "i", and "dzs" in Hungarian follows
   "dz" and precedes "g".

Example
// Run this code
 #include <clocale>
 #include <cstring>
 #include <iostream>
 int main()
 {
     std::setlocale(LC_COLLATE, "cs_CZ.utf8");
     // Alternatively, ISO-8859-2 (a.k.a. Latin-2)
     // may also work on some OS:
     // std::setlocale(LC_COLLATE, "cs_CZ.iso88592");
     const char* s1 = "hrnec";
     const char* s2 = "chrt";
     std::cout << "In the Czech locale: ";
     if (std::strcoll(s1, s2) < 0)
         std::cout << s1 << " before " << s2 << '\n';
     else
         std::cout << s2 << " before " << s1 << '\n';
     std::cout << "In lexicographical comparison: ";
     if (std::strcmp(s1, s2) < 0)
         std::cout << s1 << " before " << s2 << '\n';
     else
         std::cout << s2 << " before " << s1 << '\n';
 }

Output:
 In the Czech locale: hrnec before chrt
 In lexicographical comparison: chrt before hrnec

See also
   wcscoll compares two wide strings in accordance to the current locale
              (function)
   do_compare compares two strings using this facet's collation rules
   [virtual] (virtual protected member function of std::collate<CharT>)
              transform a string so that strcmp would produce the same result as
   strxfrm strcoll
              (function)
   C documentation for
   strcoll