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A shared_future object behaves like a future object, except that it can be copied, and that more than one shared_future can share ownership over their end of a shared state. They also allow the value in the shared state to be retrieved multiple times once ready.
shared_future objects can be implicitly converted from future objects (see its constructor), or explicitly obtained by calling future::share. In both cases, the future object from which it is obtained transfers its association with the shared state to the shared_future and becomes itself non-valid.
The lifetime of the shared state lasts at least until the last object with which it is associated is destroyed. Retrieving the value from a shared_future (with member get) does not release its ownership over the shared state (unlike with futures). Therefore, if associated to shared_future objects, the shared state can survive the object from which it was obtained in the first place (if any).
They operate in the same way as the unspecialized template, except for the return value of their shared_future::get member function.
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
<future>
classes
-
futureC++11
-
future_errorC++11
-
packaged_taskC++11
-
promiseC++11
-
shared_futureC++11
-
enum classes
-
future_errcC++11
-
future_statusC++11
-
launchC++11
-
functions
-
asyncC++11
-
future_categoryC++11
-
shared_future
-
shared_future::~shared_futureC++11
-
shared_future::shared_futureC++11
member functions
-
shared_future::getC++11
-
shared_future::operator=C++11
-
shared_future::validC++11
-
shared_future::waitC++11
-
shared_future::wait_forC++11
-
shared_future::wait_untilC++11
-
class template
<future>
std::shared_future
template <class T> shared_future;template <class R&> shared_future<R&>; // specialization : T is a reference type (R&)template <> shared_future<void>; // specialization : T is void
Shared future
shared_future objects can be implicitly converted from future objects (see its constructor), or explicitly obtained by calling future::share. In both cases, the future object from which it is obtained transfers its association with the shared state to the shared_future and becomes itself non-valid.
The lifetime of the shared state lasts at least until the last object with which it is associated is destroyed. Retrieving the value from a shared_future (with member get) does not release its ownership over the shared state (unlike with futures). Therefore, if associated to shared_future objects, the shared state can survive the object from which it was obtained in the first place (if any).
Member functions
- (constructor)
- Construct shared_future (public member function)
- (destructor)
- Destroy shared_future (public member function)
- operator=
- Assign shared future (public member function)
- get
- Get value (public member function)
- valid
- Check for valid shared state (public member function)
- wait
- Wait for ready (public member function)
- wait_for
- Wait for ready during time span (public member function)
- wait_until
- Wait for ready until time point (public member function)
Template specializations
Two specific shared_future specializations are declared in <future>: |
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Spotted an error? contact us