std::regex_search

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

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)

Execution support library (C++26)

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)

 

Template:ddcl list begin <tr class="t-dsc-header">

<td>

Defined in header <regex>

</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td >

template< class BidirIt,

          class Alloc, class CharT, class Traits >
bool regex_search( BidirIt first, BidirIt last,
                   std::match_results<BidirIt,Alloc>& m,
                   const std::basic_regex<CharT,Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (1) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class Alloc, class CharT, class Traits >

bool regex_search( const CharT* str,
                   std::match_results<BidirIt,Alloc>& m,
                   const std::basic_regex<CharT,Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (2) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class STraits, class SAlloc,

          class Alloc, class CharT, class Traits >
bool regex_search( const std::basic_string<CharT,STraits,SAlloc>& s,
                   std::match_results<
                       typename std::basic_string<CharT,STraits,SAlloc>::const_iterator,
                       Alloc
                   >& m,
                   const std::basic_regex<CharT, Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (3) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class BidirIt,

          class CharT, class Traits >
bool regex_search( BidirIt first, BidirIt last,
                   const std::basic_regex<CharT,Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (4) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class CharT, class Traits >

bool regex_search( const CharT* str,
                   const std::basic_regex<CharT,Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (5) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class STraits, class SAlloc,

          class CharT, class Traits >
bool regex_search( const std::basic_string<CharT,STraits,SAlloc>& s,
                   const std::basic_regex<CharT,Traits>& e,
                   std::regex_constants::match_flag_type flags =

                       std::regex_constants::match_default );

</td>

<td > (6) </td> <td > (since C++11) </td> </tr> Template:ddcl list end

1) Determines if there is a match between the regular express e and some subsequence in the target character sequence [first,last). Match results are returned in m.

2) Returns std::regex_search(str, str + std::char_traits<CharT>::length(str), m, e, flags).

3) Returns std::regex_search(s.begin(), s.end(), m, e, flags).

4) The same as (1), omitting the match results.

5) Returns std::regex_search(str, str + std::char_traits<CharT>::length(str), e, flags).

6) Returns std::regex_search(s.begin(), s.end(), e, flags).

Note that regex_search can successfully match any subsequence of the given sequence, whereas std::regex_match will only return true if the regular expression matches the entire sequence.

Parameters

first, last	-	the target character range
m	-	the match results
str	-	a target character null-terminated C-style string
s	-	a target character std::basic_string
e	-	the std::regex
flags	-	the match flags
Type requirements
- BidirIt must meet the requirements of LegacyBidirectionalIterator.
- Alloc must meet the requirements of Allocator.

Return value

Returns true if a match exists, false otherwise. In either case, the object m is updated, as follows:

If the match does not exist:

m.ready() == true

m.empty() == true

m.size() == 0

If the match exists:

m.ready()	true
m.empty()	false
m.size()	number of subexpressions plus 1, that is, 1+e.mark_count()
m.prefix().first	first
m.prefix().second	m[0].first
m.prefix().matched	m.prefix().first != m.prefix().second
m.suffix().first	m[0].second
m.suffix().second	last
m.suffix().matched	m.suffix().first != m.suffix().second
m[0].first	the start of the matching sequence
m[0].second	the end of the matching sequence
m[0].matched	true if a match was found, false otherwise
m[n].first	the start of the sequence that matched sub-expression n, or last if the subexpression did not participate in the match
m[n].second	the end of the sequence that matched sub-expression n, or last if the subexpression did not participate in the match
m[n].matched	true if sub-expression n participated in the match, false otherwise

See also

Template:cpp/regex/dcl list basic regexTemplate:cpp/regex/dcl list match resultsTemplate:cpp/regex/dcl list regex match