Standard library header <mutex> (C++11)

 

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External libraries

 

Standard Library headers

Note: a slash '/' in a revision mark means that the header was deprecated and/or removed.

Language Support
<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11)   <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
Concepts
<concepts> (C++20)
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error> (C++11)
General utilities
<utility> <memory> <memory_resource> (C++17) <scoped_allocator> (C++11)   <expected> (C++23)	<bitset> <tuple> (C++11) <optional> (C++17) <any> (C++17)	<variant> (C++17) <type_traits> (C++11) <ratio> (C++11) <chrono> (C++11)	<typeindex> (C++11) <functional> <stacktrace> (C++23) <ctime>
Strings
<string> <string_view> (C++17) <cstring>	<charconv> (C++17) <format> (C++20)	<cctype> <cwctype>	<cwchar> <cuchar> (C++11)
Localization
<locale> <clocale>	<codecvt> (C++11/17)
Containers
<span> (C++20) <array> (C++11) <vector>	<deque> <forward_list> (C++11) <list>	<map> <set> <queue>	<unordered_map> (C++11) <unordered_set> (C++11) <stack>
Iterators
<iterator>
Ranges
<ranges> (C++20)
Algorithms
<algorithm>	<execution> (C++17)
Numerics
<complex> <random> (C++11)	<valarray> <numeric>	<bit> (C++20) <numbers> (C++20)	<cfenv> (C++11) <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<syncstream> (C++20) <spanstream> (C++23) <sstream> <fstream>	<cstdio> <cinttypes> (C++11) <strstream> (C++98/)
Regular expressions
<regex> (C++11)
Filesystem support
<filesystem> (C++17)
Thread support
<thread> (C++11) <atomic> (C++11) <mutex> (C++11)	<shared_mutex> (C++14) <condition_variable> (C++11)   <future> (C++11)	<stop_token> (C++20) <semaphore> (C++20)	<latch> (C++20) <barrier> (C++20)
C compatibility
<cstdbool> (C++11/17/20) <ccomplex> (C++11/17/20)	<ctgmath> (C++11/17/20) <cstdalign> (C++11/17/20)	<ciso646> (until C++20) <stdatomic.h>

 

This header is part of the thread support library.

Classes
mutex (C++11)	provides basic mutual exclusion facility (class)
timed_mutex (C++11)	provides mutual exclusion facility which implements locking with a timeout (class)
recursive_mutex (C++11)	provides mutual exclusion facility which can be locked recursively by the same thread (class)
recursive_timed_mutex (C++11)	provides mutual exclusion facility which can be locked recursively by the same thread and implements locking with a timeout (class)
lock_guard (C++11)	implements a strictly scope-based mutex ownership wrapper (class template)
unique_lock (C++11)	implements movable mutex ownership wrapper (class template)
scoped_lock (C++17)	deadlock-avoiding RAII wrapper for multiple mutexes (class template)
defer_lock_ttry_to_lock_tadopt_lock_t (C++11)(C++11)(C++11)	tag type used to specify locking strategy (class)
once_flag (C++11)	helper object to ensure that call_once invokes the function only once (class)
Constants
defer_locktry_to_lockadopt_lock (C++11)(C++11)(C++11)	tag constants used to specify locking strategy (constant)
Functions
try_lock (C++11)	attempts to obtain ownership of mutexes via repeated calls to try_lock (function template)
lock (C++11)	locks specified mutexes, blocks if any are unavailable (function template)
call_once (C++11)	invokes a function only once even if called from multiple threads (function template)
std::swap(std::unique_lock) (C++11)	specialization of std::swap for unique_lock (function template)

Synopsis

namespace std {
  class mutex;
  class recursive_mutex;
  class timed_mutex;
  class recursive_timed_mutex;
 
  struct defer_lock_t { explicit defer_lock_t() = default; };
  struct try_to_lock_t { explicit try_to_lock_t() = default; };
  struct adopt_lock_t { explicit adopt_lock_t() = default; };
 
  inline constexpr defer_lock_t  defer_lock { };
  inline constexpr try_to_lock_t try_to_lock { };
  inline constexpr adopt_lock_t  adopt_lock { };
 
  template<class Mutex> class lock_guard;
  template<class... MutexTypes> class scoped_lock;
  template<class Mutex> class unique_lock;
 
  template<class Mutex>
    void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
 
  template<class L1, class L2, class... L3> int try_lock(L1&, L2&, L3&...);
  template<class L1, class L2, class... L3> void lock(L1&, L2&, L3&...);
 
  struct once_flag;
 
  template<class Callable, class... Args>
    void call_once(once_flag& flag, Callable&& func, Args&&... args);
}

Class std::mutex

namespace std {
  class mutex {
  public:
    constexpr mutex() noexcept;
    ~mutex();
 
    mutex(const mutex&) = delete;
    mutex& operator=(const mutex&) = delete;
 
    void lock();
    bool try_lock();
    void unlock();
 
    using native_handle_type = /* implementation-defined */;
    native_handle_type native_handle();
  };
}

Class std::recursive_mutex

namespace std {
  class recursive_mutex {
  public:
    recursive_mutex();
    ~recursive_mutex();
 
    recursive_mutex(const recursive_mutex&) = delete;
    recursive_mutex& operator=(const recursive_mutex&) = delete;
 
    void lock();
    bool try_lock() noexcept;
    void unlock();
 
    using native_handle_type = /* implementation-defined */;
    native_handle_type native_handle();
  };
}

Class std::timed_mutex

namespace std {
  class timed_mutex {
  public:
    timed_mutex();
    ~timed_mutex();
 
    timed_mutex(const timed_mutex&) = delete;
    timed_mutex& operator=(const timed_mutex&) = delete;
 
    void lock();    // blocking
    bool try_lock();
    template<class Rep, class Period>
      bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
    template<class Clock, class Duration>
      bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
    void unlock();
 
    using native_handle_type = /* implementation-defined */;
    native_handle_type native_handle();
  };
}

Class std::recursive_timed_mutex

namespace std {
  class recursive_timed_mutex {
  public:
    recursive_timed_mutex();
    ~recursive_timed_mutex();
 
    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
 
    void lock();    // blocking
    bool try_lock() noexcept;
    template<class Rep, class Period>
      bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
    template<class Clock, class Duration>
      bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
    void unlock();
 
    using native_handle_type = /* implementation-defined */;
    native_handle_type native_handle();
  };
}

Class template std::lock_guard

namespace std {
  template<class Mutex>
  class lock_guard {
  public:
    using mutex_type = Mutex;
 
    explicit lock_guard(mutex_type& m);
    lock_guard(mutex_type& m, adopt_lock_t);
    ~lock_guard();
 
    lock_guard(const lock_guard&) = delete;
    lock_guard& operator=(const lock_guard&) = delete;
 
  private:
    mutex_type& pm;             // exposition only
  };
}

Class template std::scoped_lock

namespace std {
  template<class... MutexTypes>
  class scoped_lock {
  public:
    using mutex_type = Mutex;   // If MutexTypes... consists of the single type Mutex
 
    explicit scoped_lock(MutexTypes&... m);
    explicit scoped_lock(adopt_lock_t, MutexTypes&... m);
    ~scoped_lock();
 
    scoped_lock(const scoped_lock&) = delete;
    scoped_lock& operator=(const scoped_lock&) = delete;
 
  private:
    tuple<MutexTypes&...> pm;   // exposition only
  };
}

Class template std::unique_lock

namespace std {
  template<class Mutex>
  class unique_lock {
  public:
    using mutex_type = Mutex;
 
    // construct/copy/destroy
    unique_lock() noexcept;
    explicit unique_lock(mutex_type& m);
    unique_lock(mutex_type& m, defer_lock_t) noexcept;
    unique_lock(mutex_type& m, try_to_lock_t);
    unique_lock(mutex_type& m, adopt_lock_t);
    template<class Clock, class Duration>
      unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
    template<class Rep, class Period>
      unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
    ~unique_lock();
 
    unique_lock(const unique_lock&) = delete;
    unique_lock& operator=(const unique_lock&) = delete;
 
    unique_lock(unique_lock&& u) noexcept;
    unique_lock& operator=(unique_lock&& u);
 
    // locking
    void lock();
    bool try_lock();
 
    template<class Rep, class Period>
      bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
    template<class Clock, class Duration>
      bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
 
    void unlock();
 
    // modifiers
    void swap(unique_lock& u) noexcept;
    mutex_type* release() noexcept;
 
    // observers
    bool owns_lock() const noexcept;
    explicit operator bool () const noexcept;
    mutex_type* mutex() const noexcept;
 
  private:
    mutex_type* pm;             // exposition only
    bool owns;                  // exposition only
  };
 
  template<class Mutex>
    void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
}

Class std::once_flag

namespace std {
  struct once_flag {
    constexpr once_flag() noexcept;
 
    once_flag(const once_flag&) = delete;
    once_flag& operator=(const once_flag&) = delete;
  };
}