std::regex_iterator<BidirIt,CharT,Traits>::regex_iterator

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Regular expressions library

Classes

basic_regex (C++11)

sub_match (C++11)

match_results (C++11)

Algorithms

regex_match (C++11)

regex_search (C++11)

regex_replace (C++11)

Iterators

regex_iterator (C++11)

regex_token_iterator (C++11)

Exceptions

regex_error (C++11)

Traits

regex_traits (C++11)

Constants

syntax_option_type (C++11)

match_flag_type (C++11)

error_type (C++11)

Regex Grammar

Modified ECMAScript-262 (C++11)

 

std::regex_iterator

Member Functions

regex_iterator::regex_iterator

regex_iterator::operator=

Comparisons

regex_iterator::operator==regex_iterator::operator!= (until C++20)

Observers

regex_iterator::operator*regex_iterator::operator->

Modifiers

regex_iterator::operator++regex_iterator::operator++(int)

 

regex_iterator();	(1)	(since C++11)
regex_iterator( BidirIt a, BidirIt b,                 const regex_type& re,                 std::regex_constants::match_flag_type m =                     std::regex_constants::match_default );	(2)	(since C++11)
regex_iterator( const regex_iterator& );	(3)	(since C++11)
regex_iterator( BidirIt, BidirIt,                 const regex_type&&,                 std::regex_constants::match_flag_type =                     std::regex_constants::match_default ) = delete;	(4)	(since C++11)

Constructs a new regex_iterator:

1) Default constructor. Constructs an end-of-sequence iterator.

2) Constructs a regex_iterator from the sequence of characters [a, b), the regular expression re, and a flag m that governs matching behavior. This constructor performs an initial call to std::regex_search with this data. If the result of this initial call is false, *this is set to an end-of-sequence iterator.

3) Copies a regex_iterator.

4) The overload (2) is not allowed to be called with a temporary regex, since the returned iterator would be immediately invalidated.

Parameters

a	-	LegacyBidirectionalIterator to the beginning of the target character sequence
b	-	LegacyBidirectionalIterator to the end of the target character sequence
re	-	regular expression used to search the target character sequence
m	-	flags that govern the behavior of re

Example

Run this code

#include <iostream>
#include <regex>
#include <string_view>
 
int main()
{
    constexpr std::string_view str{"#ONE:*p=&Mass; #Two:MOV %rd,42"};
    const std::regex re("[a-w]");
 
    // create regex_iterator, overload (2)
    auto it = std::regex_iterator<std::string_view::iterator>{
        str.cbegin(), str.cend(),
        re // re is lvalue; if an immediate expression was used
           // instead, e.g. std::regex{"[a-z]"}, this would
           // produce an error - overload (4) is deleted
    };
 
    for (decltype(it) last /* overload (1) */; it != last; ++it)
        std::cout << (*it).str();
}

Output:

password

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 2332	C++11	a regex_iterator constructed from a temporary basic_regex became invalid immediately	such construction is disallowed via a deleted overload