Types

1. basic_outcome<T, EC, EP, NoValuePolicy>

   A type carrying one of (i) a successful T (ii) a disappointment EC (iii) a failure EP (iv) both a disappointment EC and a failure EP, with NoValuePolicy specifying what to do if one tries to read state which isn’t there.

   1. basic_outcome() = delete

      The default constructor (disabled).

   2. basic_outcome(basic_outcome &&)

      Move constructor. Constexpr, triviality and noexcept propagating.

   3. basic_outcome(const basic_outcome &)

      Copy constructor. Constexpr, triviality and noexcept propagating.

   4. basic_outcome &operator=(basic_outcome &&)

      Move assignment. Constexpr, triviality and noexcept propagating.

   5. basic_outcome &operator=(const basic_outcome &)

      Copy assignment. Constexpr, triviality and noexcept propagating.

   6. ~basic_outcome()

      Destructor. Constexpr, triviality and noexcept propagating.

   7. basic_outcome(Args...) = delete

      Disabling catchall constructor used to give useful diagnostic error when trying to use non-inplace constructors when predicate::constructors_enabled is false.

   8. basic_outcome(X &&) = delete

      Disabling implicit constructor used to give useful diagnostic error when trying to use implicit constructors when predicate::implicit_constructors_enabled is false.

   9. basic_outcome(R &&)

      Implicit value_type constructor. Available if predicate::enable_value_converting_constructor<R> is true. Constexpr, triviality and noexcept propagating.

   10. basic_outcome(S &&)

       Implicit error_type constructor. Available if predicate::enable_error_converting_constructor<S> is true. Constexpr, triviality and noexcept propagating.

   11. basic_outcome(ErrorCondEnum &&)

       Implicit error_type from ErrorCondEnum constructor. Available if predicate::enable_error_condition_converting_constructor<ErrorCondEnum> is true. Constexpr, triviality and noexcept propagating.

   12. basic_outcome(P &&)

       Implicit exception_type constructor. Available if predicate::enable_exception_converting_constructor<P> is true. Constexpr, triviality and noexcept propagating.

   13. basic_outcome(S &&, P &&)

       Implicit error_type + exception_type constructor. Available if predicate::enable_error_exception_converting_constructor<S, P> is true. Constexpr, triviality and noexcept propagating.

   14. explicit basic_outcome(concepts::value_or_error<T, E> &&)

       Explicit converting constructor from concepts::value_or_error<T, E> concept matching types. Available if convert::value_or_error<> permits it. Constexpr, triviality and noexcept propagating.

   15. explicit basic_outcome(const basic_outcome<A, B, C, D> &)

       Explicit converting copy constructor from compatible basic_outcome. Available if predicate::enable_compatible_conversion<A, B, C, D> is true. Constexpr, triviality and noexcept propagating.

   16. explicit basic_outcome(basic_outcome<A, B, C, D> &&)

       Explicit converting move constructor from compatible basic_outcome. Available if predicate::enable_compatible_conversion<A, B, C, D> is true. Constexpr, triviality and noexcept propagating.

   17. explicit basic_outcome(const basic_result<A, B, C> &)

       Explicit converting copy constructor from compatible basic_result. Available if predicate::enable_compatible_conversion<A, B, void, C> is true. Constexpr, triviality and noexcept propagating.

   18. explicit basic_outcome(basic_result<A, B, C> &&)

       Explicit converting move constructor from compatible basic_result. Available if predicate::enable_compatible_conversion<A, B, void, C> is true. Constexpr, triviality and noexcept propagating.

   19. explicit basic_outcome(const basic_result<A, B, C> &)

       Explicit converting copy constructor from compatible basic_result. Available if predicate::enable_make_error_code_compatible_conversion<A, B, void, C> is true. Constexpr, triviality and noexcept propagating.

   20. explicit basic_outcome(basic_result<A, B, C> &&)

       Explicit converting move constructor from compatible basic_result. Available if predicate::enable_make_error_code_compatible_conversion<A, B, void, C> is true. Constexpr, triviality and noexcept propagating.

   21. explicit basic_outcome(in_place_type_t<value_type_if_enabled>, Args ...)

       Explicit inplace value constructor. Available if predicate::enable_inplace_value_constructor<Args ...> is true. Constexpr, triviality and noexcept propagating.

   22. explicit basic_outcome(in_place_type_t<value_type_if_enabled>, std::initializer_list<U>, Args ...)

       Explicit inplace value constructor. Available if predicate::enable_inplace_value_constructor<std::initializer_list<U>, Args ...> is true. Constexpr, triviality and noexcept propagating.

   23. explicit basic_outcome(in_place_type_t<error_type_if_enabled>, Args ...)

       Explicit inplace error constructor. Available if predicate::enable_inplace_error_constructor<Args ...> is true. Constexpr, triviality and noexcept propagating.

   24. explicit basic_outcome(in_place_type_t<error_type_if_enabled>, std::initializer_list<U>, Args ...)

       Explicit inplace error constructor. Available if predicate::enable_inplace_error_constructor<std::initializer_list<U>, Args ...> is true. Constexpr, triviality and noexcept propagating.

   25. explicit basic_outcome(in_place_type_t<exception_type_if_enabled>, Args ...)

       Explicit inplace exception constructor. Available if predicate::enable_inplace_exception_constructor<Args ...> is true. Constexpr, triviality and noexcept propagating.

   26. explicit basic_outcome(in_place_type_t<exception_type_if_enabled>, std::initializer_list<U>, Args ...)

       Explicit inplace exception constructor. Available if predicate::enable_inplace_exception_constructor<std::initializer_list<U>, Args ...> is true. Constexpr, triviality and noexcept propagating.

   27. basic_outcome(A1 &&, A2 &&, Args ...)

       Implicit inplace value or error or exception constructor. Available if predicate::enable_inplace_value_error_exception_constructor<A1, A2, Args ...> is true. Constexpr, triviality and noexcept propagating.

   28. basic_outcome(const success_type<T> &)

       Implicit value-from-success-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<T, void, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   29. basic_outcome(success_type<T> &&)

       Implicit value-from-success-type-sugar move constructor. Available if predicate::enable_compatible_conversion<T, void, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   30. basic_outcome(const failure_type<EC> &)

       Implicit error-from-failure-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<void, EC, void, void> is true. Constexpr, triviality and noexcept propagating.

   31. basic_outcome(failure_type<EC> &&)

       Implicit error-from-failure-type-sugar move constructor. Available if predicate::enable_compatible_conversion<void, EC, void, void> is true. Constexpr, triviality and noexcept propagating.

   32. basic_outcome(const failure_type<EC> &)

       Implicit error-from-failure-type-sugar copy constructor. Available if predicate::enable_make_error_code_compatible_conversion<void, EC, void, void> is true. Constexpr, triviality and noexcept propagating.

   33. basic_outcome(failure_type<EC> &&)

       Implicit error-from-failure-type-sugar move constructor. Available if predicate::enable_make_error_code_compatible_conversion<void, EC, void, void> is true. Constexpr, triviality and noexcept propagating.

   34. basic_outcome(const failure_type<EP> &)

       Implicit exception-from-failure-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<void, void, EP, void> is true. Constexpr, triviality and noexcept propagating.

   35. basic_outcome(failure_type<EP> &&)

       Implicit exception-from-failure-type-sugar move constructor. Available if predicate::enable_compatible_conversion<void, void, EP, void> is true. Constexpr, triviality and noexcept propagating.

   36. basic_outcome(const failure_type<EC, EP> &)

       Implicit error-and-exception-from-failure-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<void, EC, EP, void> is true. Constexpr, triviality and noexcept propagating.

   37. basic_outcome(failure_type<EC, EP> &&)

       Implicit error-and-exception-from-failure-type-sugar move constructor. Available if predicate::enable_compatible_conversion<void, EC, EP, void> is true. Constexpr, triviality and noexcept propagating.

   38. explicit operator bool() const noexcept

       Returns true if a value is present. Constexpr, never throws.

   39. bool has_value() const noexcept

       Returns true if a value is present. Constexpr, never throws.

   40. bool has_error() const noexcept

       Returns true if an error is present. Constexpr, never throws.

   41. bool has_exception() const noexcept

       Returns true if an exception is present. Constexpr, never throws.

   42. bool has_failure() const noexcept

       Returns true if there is either an error or an exception. Constexpr, never throws.

   43. value_type &assume_value() & noexcept

       Narrow contract lvalue reference observer of any value present. Constexpr propagating, never throws.

   44. const value_type &assume_value() const & noexcept

       Narrow contract const lvalue reference observer of any value present. Constexpr propagating, never throws.

   45. value_type &&assume_value() && noexcept

       Narrow contract rvalue reference observer of any value present. Constexpr propagating, never throws.

   46. const value_type &&assume_value() const && noexcept

       Narrow contract const rvalue reference observer of any value present. Constexpr propagating, never throws.

   47. value_type &value() &

       Wide contract lvalue reference observer of any value present. Constexpr propagating.

   48. const value_type &value() const &

       Wide contract const lvalue reference observer of any value present. Constexpr propagating.

   49. value_type &&value() &&

       Wide contract rvalue reference observer of any value present. Constexpr propagating.

   50. const value_type &&value() const &&

       Wide contract const rvalue reference observer of any value present. Constexpr propagating.

   51. error_type &assume_error() & noexcept

       Narrow contract lvalue reference observer of the stored error. Constexpr propagating, never throws.

   52. const error_type &assume_error() const & noexcept

       Narrow contract const lvalue reference observer of the stored error. Constexpr propagating, never throws.

   53. error_type &&assume_error() && noexcept

       Narrow contract rvalue reference observer of the stored error. Constexpr propagating, never throws.

   54. const error_type &&assume_error() const && noexcept

       Narrow contract const rvalue reference observer of the stored error. Constexpr propagating, never throws.

   55. error_type &error() &

       Wide contract lvalue reference observer of the stored error. Constexpr propagating.

   56. const error_type &error() const &

       Wide contract const lvalue reference observer of the stored error. Constexpr propagating.

   57. error_type &&error() &&

       Wide contract rvalue reference observer of the stored error. Constexpr propagating.

   58. const error_type &&error() const &&

       Wide contract const rvalue reference observer of the stored error. Constexpr propagating.

   59. exception_type &assume_exception() & noexcept

       Narrow contract lvalue reference observer of the stored exception. Constexpr propagating, never throws.

   60. const exception_type &assume_exception() const & noexcept

       Narrow contract const lvalue reference observer of the stored exception. Constexpr propagating, never throws.

   61. const exception_type &&assume_exception() const && noexcept

       Narrow contract const rvalue reference observer of the stored exception. Constexpr propagating, never throws.

   62. exception_type &&assume_exception() && noexcept

       Narrow contract rvalue reference observer of the stored exception. Constexpr propagating, never throws.

   63. exception_type &exception() &

       Wide contract lvalue reference observer of the stored exception. Constexpr propagating.

   64. const exception_type &exception() const &

       Wide contract const lvalue reference observer of the stored exception. Constexpr propagating.

   65. exception_type &&exception() &&

       Wide contract rvalue reference observer of the stored exception. Constexpr propagating.

   66. const exception_type &&exception() const &&

       Wide contract const rvalue reference observer of the stored exception. Constexpr propagating.

   67. exception_type failure() const noexcept

       Synthesising observer of the stored exception or error. Available if the traits is_error_code_available<T> and is_exception_ptr_available<T> are both true. Never throws.

   68. bool operator==(const basic_result<A, B, C> &) const

       Returns true if this outcome compares equal to the other result. Constexpr and noexcept propagating.

   69. bool operator==(const basic_outcome<A, B, C, D> &) const

       Returns true if this outcome compares equal to the other outcome. Constexpr and noexcept propagating.

   70. bool operator==(const success_type<A> &) const

       Returns true if this result compares equal to the success type sugar. Constexpr and noexcept propagating.

   71. bool operator==(const failure_type<A, B> &) const

       Returns true if this outcome compares equal to the failure type sugar. Constexpr and noexcept propagating.

   72. bool operator!=(const basic_result<A, B, C> &) const

       Returns true if this outcome does not compare equal to the other result. Constexpr and noexcept propagating.

   73. bool operator!=(const basic_outcome<A, B, C, D> &) const

       Returns true if this outcome does not compare equal to the other outcome. Constexpr and noexcept propagating.

   74. bool operator!=(const success_type<A> &) const

       Returns true if this outcome does not compare equal to the success type sugar. Constexpr and noexcept propagating.

   75. bool operator!=(const failure_type<A, B> &) const

       Returns true if this outcome does not compare equal to the failure type sugar. Constexpr and noexcept propagating.

   76. void swap(basic_outcome &)

       Swap one basic_outcome with another, with the strong guarantee. Noexcept propagating.

   77. failure_type<error_type, exception_type> as_failure() const &

       Return the output from free function failure() containing a copy of any errored and/or excepted state.

   78. failure_type<error_type, exception_type> as_failure() &&

       Return the output from free function failure() containing a move of any errored and/or excepted state.

2. basic_result<T, E, NoValuePolicy>

   A sum type carrying either a successful T, or a disappointment E, with NoValuePolicy specifying what to do if one tries to read state which isn’t there.

   1. basic_result() = delete

      The default constructor (disabled).

   2. basic_result(basic_result &&)

      Move constructor. Constexpr, triviality and noexcept propagating.

   3. basic_result(const basic_result &)

      Copy constructor. Constexpr, triviality and noexcept propagating.

   4. basic_result &operator=(basic_result &&)

      Move assignment. Constexpr, triviality and noexcept propagating.

   5. basic_result &operator=(const basic_result &)

      Copy assignment. Constexpr, triviality and noexcept propagating.

   6. ~basic_result()

      Destructor. Constexpr, triviality and noexcept propagating.

   7. basic_result(Args...) = delete

      Disabling catchall constructor used to give useful diagnostic error when trying to use non-inplace constructors when predicate::constructors_enabled is false.

   8. basic_result(X &&) = delete

      Disabling implicit constructor used to give useful diagnostic error when trying to use implicit constructors when predicate::implicit_constructors_enabled is false.

   9. basic_result(R &&)

      Implicit value_type constructor. Available if predicate::enable_value_converting_constructor<R> is true. Constexpr, triviality and noexcept propagating.

   10. basic_result(S &&)

       Implicit error_type constructor. Available if predicate::enable_error_converting_constructor<S> is true. Constexpr, triviality and noexcept propagating.

   11. basic_result(ErrorCondEnum &&)

       Implicit error_type from ErrorCondEnum constructor. Available if predicate::enable_error_condition_converting_constructor<ErrorCondEnum> is true. Constexpr, triviality and noexcept propagating.

   12. explicit basic_result(concepts::value_or_error<T, E> &&)

       Explicit converting constructor from concepts::value_or_error<T, E> concept matching types. Available if convert::value_or_error<> permits it. Constexpr, triviality and noexcept propagating.

   13. explicit basic_result(const basic_result<R, S, P> &)

       Explicit converting copy constructor from compatible basic_result. Available if predicate::enable_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   14. explicit basic_result(basic_result<R, S, P> &&)

       Explicit converting move constructor from compatible basic_result. Available if predicate::enable_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   15. explicit basic_result(const basic_result<R, S, P> &)

       Explicit converting copy constructor from compatible basic_result. Available if predicate::enable_make_error_code_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   16. explicit basic_result(basic_result<R, S, P> &&)

       Explicit converting move constructor from compatible basic_result. Available if predicate::enable_make_error_code_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   17. explicit basic_result(const basic_result<R, S, P> &)

       Explicit converting copy constructor from compatible basic_result. Available if predicate::enable_make_exception_ptr_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   18. explicit basic_result(basic_result<R, S, P> &&)

       Explicit converting move constructor from compatible basic_result. Available if predicate::enable_make_exception_ptr_compatible_conversion<R, S, P> is true. Constexpr, triviality and noexcept propagating.

   19. explicit basic_result(in_place_type_t<value_type_if_enabled>, Args ...)

       Explicit inplace value constructor. Available if predicate::enable_inplace_value_constructor<Args ...> is true. Constexpr, triviality and noexcept propagating.

   20. explicit basic_result(in_place_type_t<value_type_if_enabled>, std::initializer_list<U>, Args ...)

       Explicit inplace value constructor. Available if predicate::enable_inplace_value_constructor<std::initializer_list<U>, Args ...> is true. Constexpr, triviality and noexcept propagating.

   21. explicit basic_result(in_place_type_t<error_type_if_enabled>, Args ...)

       Explicit inplace error constructor. Available if predicate::enable_inplace_error_constructor<Args ...> is true. Constexpr, triviality and noexcept propagating.

   22. explicit basic_result(in_place_type_t<error_type_if_enabled>, std::initializer_list<U>, Args ...)

       Explicit inplace error constructor. Available if predicate::enable_inplace_error_constructor<std::initializer_list<U>, Args ...> is true. Constexpr, triviality and noexcept propagating.

   23. basic_result(A1 &&, A2 &&, Args ...)

       Implicit inplace value or error constructor. Available if predicate::enable_inplace_value_error_constructor<A1, A2, Args ...> is true. Constexpr, triviality and noexcept propagating.

   24. basic_result(const success_type<T> &)

       Implicit value-from-success-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<T, void, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   25. basic_result(success_type<T> &&)

       Implicit value-from-success-type-sugar move constructor. Available if predicate::enable_compatible_conversion<T, void, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   26. basic_result(const failure_type<T> &)

       Implicit error-from-failure-type-sugar copy constructor. Available if predicate::enable_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   27. basic_result(failure_type<T> &&)

       Implicit error-from-failure-type-sugar move constructor. Available if predicate::enable_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   28. basic_result(const failure_type<T> &)

       Implicit error-from-failure-type-sugar copy constructor. Available if predicate::enable_make_error_code_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   29. basic_result(failure_type<T> &&)

       Implicit error-from-failure-type-sugar move constructor. Available if predicate::enable_make_error_code_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   30. basic_result(const failure_type<T> &)

       Implicit error-from-failure-type-sugar copy constructor. Available if predicate::enable_make_exception_ptr_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   31. basic_result(failure_type<T> &&)

       Implicit error-from-failure-type-sugar move constructor. Available if predicate::enable_make_exception_ptr_compatible_conversion<void, T, void> is true, or T is void. Constexpr, triviality and noexcept propagating.

   32. explicit operator bool() const noexcept

       Returns true if a value is present. Constexpr, never throws.

   33. bool has_value() const noexcept

       Returns true if a value is present. Constexpr, never throws.

   34. bool has_error() const noexcept

       Returns true if an error is present. Constexpr, never throws.

   35. bool has_exception() const noexcept

       Always returns false for basic_result. Constexpr, never throws.

   36. bool has_failure() const noexcept

       Returns true if there is either an error or an exception. Constexpr, never throws.

   37. bool has_lost_consistency() const noexcept

       Returns true if a preceding swap involving this object failed to preserve the strong guarantee. Constexpr, never throws.

   38. value_type &assume_value() & noexcept

       Narrow contract lvalue reference observer of any value present. Constexpr propagating, never throws.

   39. const value_type &assume_value() const & noexcept

       Narrow contract const lvalue reference observer of any value present. Constexpr propagating, never throws.

   40. value_type &&assume_value() && noexcept

       Narrow contract rvalue reference observer of any value present. Constexpr propagating, never throws.

   41. const value_type &&assume_value() const && noexcept

       Narrow contract const rvalue reference observer of any value present. Constexpr propagating, never throws.

   42. value_type &value() &

       Wide contract lvalue reference observer of any value present. Constexpr propagating.

   43. const value_type &value() const &

       Wide contract const lvalue reference observer of any value present. Constexpr propagating.

   44. value_type &&value() &&

       Wide contract rvalue reference observer of any value present. Constexpr propagating.

   45. const value_type &&value() const &&

       Wide contract const rvalue reference observer of any value present. Constexpr propagating.

   46. error_type &assume_error() & noexcept

       Narrow contract lvalue reference observer of the stored error. Constexpr propagating, never throws.

   47. const error_type &assume_error() const & noexcept

       Narrow contract const lvalue reference observer of the stored error. Constexpr propagating, never throws.

   48. error_type &&assume_error() && noexcept

       Narrow contract rvalue reference observer of the stored error. Constexpr propagating, never throws.

   49. const error_type &&assume_error() const && noexcept

       Narrow contract const rvalue reference observer of the stored error. Constexpr propagating, never throws.

   50. error_type &error() &

       Wide contract lvalue reference observer of the stored error. Constexpr propagating.

   51. const error_type &error() const &

       Wide contract const lvalue reference observer of the stored error. Constexpr propagating.

   52. error_type &&error() &&

       Wide contract rvalue reference observer of the stored error. Constexpr propagating.

   53. const error_type &&error() const &&

       Wide contract const rvalue reference observer of the stored error. Constexpr propagating.

   54. bool operator==(const basic_result<A, B, C> &) const

       Returns true if this result compares equal to the other result. Constexpr and noexcept propagating.

   55. bool operator==(const success_type<A> &) const

       Returns true if this result compares equal to the success type sugar. Constexpr and noexcept propagating.

   56. bool operator==(const failure_type<A, void> &) const

       Returns true if this result compares equal to the failure type sugar. Constexpr and noexcept propagating.

   57. bool operator!=(const basic_result<A, B, C> &) const

       Returns true if this result does not compare equal to the other result. Constexpr and noexcept propagating.

   58. bool operator!=(const success_type<A> &) const

       Returns true if this result does not compare equal to the success type sugar. Constexpr and noexcept propagating.

   59. bool operator!=(const failure_type<A, void> &) const

       Returns true if this result does not compare equal to the failure type sugar. Constexpr and noexcept propagating.

   60. void swap(basic_result &)

       Swap one basic_result with another, with the strong guarantee. Noexcept propagating.

   61. auto as_failure() const &

       Return the output from free function failure() containing a copy of any errored state.

   62. auto as_failure() &&

       Return the output from free function failure() containing a move of any errored state.

3. bad_outcome_access

   Exception type publicly inheriting from std::logic_error indicating an incorrect observation of value or error or exception occurred.

4. bad_result_access_with<EC>

   Exception type publicly inheriting from bad_result_access indicating an incorrect observation of value occurred, supplying the error value.

5. bad_result_access

   Exception type publicly inheriting from std::logic_error indicating an incorrect observation of value or error occurred.

6. eager<T, Executor = void>/atomic_eager<T, Executor = void>

   An eagerly evaluated coroutine awaitable with Outcome customisation.

7. failure_type<EC, EP = void>

   Type sugar for constructing an unsuccessful result or outcome.

8. generator<T, Executor = void>

   A lazily evaluated coroutine generator with Outcome customisation.

9. in_place_type_t<T>

   Either std::in_place_type_t<T> or a local emulation, depending on the OUTCOME_USE_STD_IN_PLACE_TYPE macro.

10. lazy<T, Executor = void>/atomic_lazy<T, Executor = void>

    A lazily evaluated coroutine awaitable with Outcome customisation.

11. success_type<T>

    Type sugar for constructing a successful result or outcome.