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<exception> typedefs | Microsoft Docs |
11/04/2016 |
article |
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2a338480-35e2-46f7-b223-52d4e84a5768 |
7 |
ghogen |
| exception_ptr | terminate_handler | unexpected_handler |
A type that describes a pointer to an exception.
typedef unspecified exception_ptr;An unspecified internal class that is used to implement the exception_ptr type.
Use an exception_ptr object to reference the current exception or an instance of a user-specified exception. In the Microsoft implementation, an exception is represented by an EXCEPTION_RECORD structure. Each exception_ptr object includes an exception reference field that points to a copy of the EXCEPTION_RECORD structure that represents the exception.
When you declare an exception_ptr variable, the variable is not associated with any exception. That is, its exception reference field is NULL. Such an exception_ptr object is called a null exception_ptr.
Use the current_exception or make_exception_ptr function to assign an exception to an exception_ptr object. When you assign an exception to an exception_ptr variable, the variable's exception reference field points to a copy of the exception. If there is insufficient memory to copy the exception, the exception reference field points to a copy of a std::bad_alloc exception. If the current_exception or make_exception_ptr function cannot copy the exception for any other reason, the function calls the terminate CRT function to exit the current process.
Despite its name, an exception_ptr object is not itself a pointer. It does not obey pointer semantics and cannot be used with the pointer member access ( ->) or indirection (*) operators. The exception_ptr object has no public data members or member functions.
Comparisons:
You can use the equal ( ==) and not-equal ( !=) operators to compare two exception_ptr objects. The operators do not compare the binary value (bit pattern) of the EXCEPTION_RECORD structures that represent the exceptions. Instead, the operators compare the addresses in the exception reference field of the exception_ptr objects. Consequently, a null exception_ptr and the NULL value compare as equal.
The type describes a pointer to a function suitable for use as a terminate_handler.
typedef void (*terminate_handler)();
The type describes a pointer to a function suitable for use as a terminate handler.
See set_terminate for an example of the use of terminate_handler.
The type describes a pointer to a function suitable for use as an unexpected_handler.
typedef void (*unexpected_handler)();
See set_unexpected for an example of the use of unexpected_handler.