class Error

Declaration

class Error { /* full declaration omitted */ };

Description

Lightweight error class with error context and mandatory checking. Instances of this class wrap a ErrorInfoBase pointer. Failure states are represented by setting the pointer to a ErrorInfoBase subclass instance containing information describing the failure. Success is represented by a null pointer value. Instances of Error also contains a 'Checked' flag, which must be set before the destructor is called, otherwise the destructor will trigger a runtime error. This enforces at runtime the requirement that all Error instances be checked or returned to the caller. There are two ways to set the checked flag, depending on what state the Error instance is in. For Error instances indicating success, it is sufficient to invoke the boolean conversion operator. E.g.: A success value *can not* be dropped. For example, just calling 'foo( < ...>)' without testing the return value will raise a runtime error, even if foo returns success. For Error instances representing failure, you must use either the handleErrors or handleAllErrors function with a typed handler. E.g.: The handleAllErrors function is identical to handleErrors, except that it has a void return type, and requires all errors to be handled and no new errors be returned. It prevents errors (assuming they can all be handled) from having to be bubbled all the way to the top-level. *All* Error instances must be checked before destruction, even if they're moved-assigned or constructed from Success values that have already been checked. This enforces checking through all levels of the call stack.

Declared at: llvm/include/llvm/Support/Error.h:155

Member Variables

private llvm::ErrorInfoBase* Payload = nullptr

Method Overview

Methods

Error()

Description

Create a success value. Prefer using 'Error::success()' for readability

Declared at: llvm/include/llvm/Support/Error.h:174

Error(const llvm::Error& Other)

Declared at: llvm/include/llvm/Support/Error.h:184

Parameters

const llvm::Error& Other

Error(llvm::Error&& Other)

Description

Move-construct an error value. The newly constructed error is considered unchecked, even if the source error had been checked. The original error becomes a checked Success value, regardless of its original state.

Declared at: llvm/include/llvm/Support/Error.h:189

Parameters

llvm::Error&& Other

Error(std::unique_ptr<ErrorInfoBase> Payload)

Description

Create an error value. Prefer using the 'make_error' function, but this constructor can be useful when "re-throwing" errors from handlers.

Declared at: llvm/include/llvm/Support/Error.h:196

Parameters

std::unique_ptr<ErrorInfoBase> Payload

void assertIsChecked()

Declared at: llvm/include/llvm/Support/Error.h:261

const void* dynamicClassID() const

Description

Returns the dynamic class id of this error, or null if this is a success value.

Declared at: llvm/include/llvm/Support/Error.h:245

bool getChecked() const

Declared at: llvm/include/llvm/Support/Error.h:289

llvm::ErrorInfoBase* getPtr() const

Declared at: llvm/include/llvm/Support/Error.h:268

template <typename ErrT>
bool isA() const

Description

Check whether one error is a subclass of another.

Declared at: llvm/include/llvm/Support/Error.h:239

Templates

ErrT

bool operator bool()

Description

Bool conversion. Returns true if this Error is in a failure state, and false if it is in an accept state. If the error is in a Success state it will be considered checked.

Declared at: llvm/include/llvm/Support/Error.h:233

void setChecked(bool V)

Declared at: llvm/include/llvm/Support/Error.h:297

Parameters

bool V

void setPtr(llvm::ErrorInfoBase* EI)

Declared at: llvm/include/llvm/Support/Error.h:278

Parameters

llvm::ErrorInfoBase* EI

static llvm::ErrorSuccess success()

Description

Create a success value.

Declared at: llvm/include/llvm/Support/Error.h:181

std::unique_ptr<ErrorInfoBase> takePayload()

Declared at: llvm/include/llvm/Support/Error.h:306

~Error()

Description

Destroy a Error. Fails with a call to abort() if the error is unchecked.

Declared at: llvm/include/llvm/Support/Error.h:225