v8  8.6.395 (node 15.0.1)
V8 is Google's open source JavaScript engine
TryCatch Class Reference

#include <v8.h>

Public Member Functions

 TryCatch (Isolate *isolate)
 ~TryCatch ()
bool HasCaught () const
bool CanContinue () const
bool HasTerminated () const
Local< ValueReThrow ()
Local< ValueException () const
V8_WARN_UNUSED_RESULT MaybeLocal< ValueStackTrace (Local< Context > context) const
Local< v8::MessageMessage () const
void Reset ()
void SetVerbose (bool value)
bool IsVerbose () const
void SetCaptureMessage (bool value)
 TryCatch (const TryCatch &)=delete
void operator= (const TryCatch &)=delete

Static Public Member Functions

static V8_WARN_UNUSED_RESULT MaybeLocal< ValueStackTrace (Local< Context > context, Local< Value > exception)
static void * JSStackComparableAddress (TryCatch *handler)


class internal::Isolate

Detailed Description

An external exception handler.

Definition at line 10083 of file v8.h.

Constructor & Destructor Documentation

◆ TryCatch() [1/2]

TryCatch ( Isolate isolate)

Creates a new try/catch block and registers it with v8. Note that all TryCatch blocks should be stack allocated because the memory location itself is compared against JavaScript try/catch blocks.

◆ ~TryCatch()

~TryCatch ( )

Unregisters and deletes this try/catch block.

◆ TryCatch() [2/2]

TryCatch ( const TryCatch )

Member Function Documentation

◆ CanContinue()

bool CanContinue ( ) const

For certain types of exceptions, it makes no sense to continue execution.

If CanContinue returns false, the correct action is to perform any C++ cleanup needed and then return. If CanContinue returns false and HasTerminated returns true, it is possible to call CancelTerminateExecution in order to continue calling into the engine.

◆ Exception()

Local<Value> Exception ( ) const

Returns the exception caught by this try/catch block. If no exception has been caught an empty handle is returned.

◆ HasCaught()

bool HasCaught ( ) const

Returns true if an exception has been caught by this try/catch block.

◆ HasTerminated()

bool HasTerminated ( ) const

Returns true if an exception has been caught due to script execution being terminated.

There is no JavaScript representation of an execution termination exception. Such exceptions are thrown when the TerminateExecution methods are called to terminate a long-running script.

If such an exception has been thrown, HasTerminated will return true, indicating that it is possible to call CancelTerminateExecution in order to continue calling into the engine.

◆ IsVerbose()

bool IsVerbose ( ) const

Returns true if verbosity is enabled.

◆ JSStackComparableAddress()

static void* JSStackComparableAddress ( TryCatch handler)

There are cases when the raw address of C++ TryCatch object cannot be used for comparisons with addresses into the JS stack. The cases are: 1) ARM, ARM64 and MIPS simulators which have separate JS stack. 2) Address sanitizer allocates local C++ object in the heap when UseAfterReturn mode is enabled. This method returns address that can be used for comparisons with addresses into the JS stack. When neither simulator nor ASAN's UseAfterReturn is enabled, then the address returned will be the address of the C++ try catch handler itself.

Definition at line 10207 of file v8.h.

◆ Message()

Returns the message associated with this exception. If there is no message associated an empty handle is returned.

◆ operator=()

void operator= ( const TryCatch )

◆ Reset()

void Reset ( )

Clears any exceptions that may have been caught by this try/catch block. After this method has been called, HasCaught() will return false. Cancels the scheduled exception if it is caught and ReThrow() is not called before.

It is not necessary to clear a try/catch block before using it again; if another exception is thrown the previously caught exception will just be overwritten. However, it is often a good idea since it makes it easier to determine which operation threw a given exception.

◆ ReThrow()

Local<Value> ReThrow ( )

Throws the exception caught by this TryCatch in a way that avoids it being caught again by this same TryCatch. As with ThrowException it is illegal to execute any JavaScript operations after calling ReThrow; the caller must return immediately to where the exception is caught.

◆ SetCaptureMessage()

void SetCaptureMessage ( bool  value)

Set whether or not this TryCatch should capture a Message object which holds source information about where the exception occurred. True by default.

◆ SetVerbose()

void SetVerbose ( bool  value)

Set verbosity of the external exception handler.

By default, exceptions that are caught by an external exception handler are not reported. Call SetVerbose with true on an external exception handler to have exceptions caught by the handler reported as if they were not caught.

◆ StackTrace() [1/2]

Returns the .stack property of the thrown object. If no .stack property is present or if this try/catch block has not caught an exception, an empty handle is returned.

◆ StackTrace() [2/2]

static V8_WARN_UNUSED_RESULT MaybeLocal<Value> StackTrace ( Local< Context context,
Local< Value exception 

Returns the .stack property of an object. If no .stack property is present an empty handle is returned.

Friends And Related Function Documentation

◆ internal::Isolate

friend class internal::Isolate

Definition at line 10236 of file v8.h.

The documentation for this class was generated from the following file: