std::operators (sub_match)

(1)	template <class I> bool operator==(const sub_match<I>& lhs, const sub_match<I>& rhs);
(2)	template <class I, class T, class A> bool operator== (const basic_string<typename iterator_traits<I>::value_type,T,A>& lhs, const sub_match& rhs);
(3)	template <class I, class T, class A> bool operator== (const sub_match& lhs, const basic_string<typename iterator_traits<I>::value_type,T,A>& rhs);
(4)	template <class I> bool operator== (const typename iterator_traits<I>::value_type* lhs, const sub_match<i>& rhs);
(5)	template <class I> bool operator== (const sub_match<i>& lhs, const typename iterator_traits<I>::value_type* rhs);
(6)	template <class I> bool operator== (const typename iterator_traits<I>::value_type& lhs, const sub_match<I>& rhs);
(7)	template <class I> bool operator== (const sub_match<I>& lhs, const typename iterator_traits<I>::value_type& rhs);
also	/* also defined for the following operators: operator!= operator< operator> operator>= operator<= with the same 7 signatures as for operator== */

Relational operators for sub_match

Returns the result of the appropriate relational operation between lhs and rhs as if both where string objects.

The function uses sub_match::compare.

Parameters

lhs, rhs: sub_match or string-like objects (to the left- and right-hand side of the operator, respectively), operating both on the same type of characters.

Return Value

true if the condition holds, and false otherwise.

Example

// sub_match relational operators
#include <iostream>
#include <regex>

int main ()
{
  using namespace std::regex_constants;

  std::cmatch m;

  std::regex_search ( "there is a needle in this haystack", m, std::regex("n\\w+") );

  if (m[0]=="needle") std::cout << "needle found!" << std::endl;

  return 0;
}