1209. match_results should be moveable

Section: 31.10.1 [re.results.const] Status: C++11 Submitter: Stephan T. Lavavej Opened: 2009-09-15 Last modified: 2016-02-10

Priority: Not Prioritized

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In Working Draft N2914, match_results lacks a move constructor and move assignment operator. Because it owns dynamically allocated memory, it should be moveable.

As far as I can tell, this isn't tracked by an active issue yet; Library Issue 723 doesn't talk about match_results.

[ 2009-09-21 Daniel provided wording. ]

[ 2009-11-18: Moved to Tentatively Ready after 5 positive votes on c++std-lib. ]

Proposed resolution:

  1. Add the following member declarations to 31.10 [re.results]/3:

    // 28.10.1, construct/copy/destroy:
    explicit match_results(const Allocator& a = Allocator());
    match_results(const match_results& m);
    match_results(match_results&& m);
    match_results& operator=(const match_results& m);
    match_results& operator=(match_results&& m);
  2. Add the following new prototype descriptions to 31.10.1 [re.results.const] using the table numbering of N3000 (referring to the table titled "match_results assignment operator effects"):

    match_results(const match_results& m);

    4 Effects: Constructs an object of class match_results, as a copy of m.

    match_results(match_results&& m);

    5 Effects: Move-constructs an object of class match_results from m satisfying the same postconditions as Table 131. Additionally the stored Allocator value is move constructed from m.get_allocator(). After the initialization of *this sets m to an unspecified but valid state.

    6 Throws: Nothing if the allocator's move constructor throws nothing.

    match_results& operator=(const match_results& m);

    7 Effects: Assigns m to *this. The postconditions of this function are indicated in Table 131.

    match_results& operator=(match_results&& m);

    8 Effects: Move-assigns m to *this. The postconditions of this function are indicated in Table 131. After the assignment, m is in a valid but unspecified state.

    9 Throws: Nothing.