# std::match_results<BidirIt,Alloc>::match_results

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< cpp‎ | regex‎ | match results

match_results() : match_results(Allocator()) {} | (1) | (since C++11)
explicit match_results( const Allocator& a ); | (2) | (since C++11)
match_results( const match_results& rhs ); | (3) | (since C++11)
match_results( const match_results& rhs, const Allocator& a ); | (4) | (since C++11)
match_results( match_results&& rhs ) noexcept; | (5) | (since C++11)
match_results( match_results&& rhs, const Allocator& a ); | (6) | (since C++11)

1) Default constructor. Constructs a match result with no established result state (ready() != true).
2) Constructs a match result with no established result state (ready() != true) using a copy of a as the allocator.
3) Copy constructor. Constructs a match result with a copy of rhs.
4) Constructs a match result with a copy of rhs, and uses a copy of a as the allocator.
5) Move constructor. Constructs a match result with the contents of rhs using move semantics. rhs is in valid, but unspecified state after the call.
6) Constructs a match result with the contents of rhs using move semantics, and uses a copy of a as the allocator. rhs is in valid, but unspecified state after the call.

### Parameters

a | - | allocator to use for all memory allocations of this container
rhs | - | another `match_results` to use as source to initialize the `match_results` with

### Exceptions

1-4) May throw implementation-defined exceptions.
6) Throws nothing if a == rhs.get_allocator() is true.

### Example

| This section is incomplete Reason: no example

### 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 2195 | C++11 | the constructors required by AllocatorAwareContainer were missing | added
P0935R0 | C++11 | default constructor was explicit | made implicit

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