class Expected

Declaration

template <class T>
class Expected { /* full declaration omitted */ };

Description

Tagged union holding either a T or a Error. This class parallels ErrorOr, but replaces error_code with Error. Since Error cannot be copied, this class replaces getError() with takeError(). It also adds an bool errorIsA <ErrT >() method for testing the error class type.

Declared at: llvm/include/llvm/Support/Error.h:433

Templates

T

Method Overview

• public Expected<T>(llvm::Error Err)
• public Expected<T>(llvm::ErrorSuccess)
• public Expected<T>(Expected<T> && Other)
• public template <typename OtherT> Expected<T>(OtherT && Val, typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * = nullptr)
• public template <class OtherT> Expected<T>(Expected<OtherT> && Other, typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * = nullptr)
• public template <class OtherT> Expected<T>(Expected<OtherT> && Other, typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * = nullptr)
• public template <typename ErrT>bool errorIsA() const
• public llvm::Expected::reference get()
• public llvm::Expected::const_reference get() const
• public bool operator bool()
• public llvm::Error takeError()
• public ~Expected<T>()

Methods

¶Expected<T>(llvm::Error Err)

Description

Create an Expected <T > error value from the given Error.

Declared at: llvm/include/llvm/Support/Error.h:455

Parameters

llvm::Error Err

¶Expected<T>(llvm::ErrorSuccess)

Description

Forbid to convert from Error::success() implicitly, this avoids having Expected <T > foo() { return Error::success(); } which compiles otherwise but triggers the assertion above.

Declared at: llvm/include/llvm/Support/Error.h:469

Parameters

llvm::ErrorSuccess

¶Expected<T>(Expected<T>&& Other)

Description

Move construct an Expected <T > value.

Declared at: llvm/include/llvm/Support/Error.h:487

Parameters

Expected<T>&& Other

¶template <typename OtherT>
Expected<T>(
    OtherT&& Val,
    typename std::enable_if<
        std::is_convertible<OtherT, T>::value>::
        type* = nullptr)

Description

Create an Expected <T > success value from the given OtherT value, which must be convertible to T.

Declared at: llvm/include/llvm/Support/Error.h:474

Templates

OtherT

Parameters

OtherT&& Val

typename std::enable_if< std::is_convertible<OtherT, T>::value>::type* = nullptr

¶template <class OtherT>
Expected<T>(
    Expected<OtherT>&& Other,
    typename std::enable_if<
        std::is_convertible<OtherT, T>::value>::
        type* = nullptr)

Description

Move construct an Expected <T > value from an Expected <OtherT >, where OtherT must be convertible to T.

Declared at: llvm/include/llvm/Support/Error.h:492

Templates

OtherT

Parameters

Expected<OtherT>&& Other

typename std::enable_if< std::is_convertible<OtherT, T>::value>::type* = nullptr

¶template <class OtherT>
Expected<T>(
    Expected<OtherT>&& Other,
    typename std::enable_if<
        !std::is_convertible<OtherT, T>::value>::
        type* = nullptr)

Description

Move construct an Expected <T > value from an Expected <OtherT >, where OtherT isn't convertible to T.

Declared at: llvm/include/llvm/Support/Error.h:501

Templates

OtherT

Parameters

Expected<OtherT>&& Other

typename std::enable_if< !std::is_convertible<OtherT, T>::value>::type* = nullptr

¶template <typename ErrT>
bool errorIsA() const

Description

Check that this Expected <T > is an error of type ErrT.

Declared at: llvm/include/llvm/Support/Error.h:544

Templates

ErrT

¶llvm::Expected::reference get()

Description

Returns a reference to the stored T value.

Declared at: llvm/include/llvm/Support/Error.h:532

¶llvm::Expected::const_reference get() const

Description

Returns a const reference to the stored T value.

Declared at: llvm/include/llvm/Support/Error.h:538

¶bool operator bool()

Description

Return false if there is an error.

Declared at: llvm/include/llvm/Support/Error.h:524

¶llvm::Error takeError()

Description

Take ownership of the stored error. After calling this the Expected <T > is in an indeterminate state that can only be safely destructed. No further calls (beside the destructor) should be made on the Expected <T > value.

Declared at: llvm/include/llvm/Support/Error.h:552

¶~Expected<T>()

Description

Destroy an Expected <T >.

Declared at: llvm/include/llvm/Support/Error.h:515