A predicate for checking whether an exception is being thrown.
Synopsis
Declared in header <boost/scope/exception_checker.hpp>
class exception_checker;Types
Name |
Description |
Predicate result type |
Member Functions
Name |
Description |
Constructs the predicate. |
|
Checks if an exception is being thrown. |
Description
On construction, the predicate captures the current number of uncaught exceptions,
which it then compares with the number of uncaught exceptions at the point when it
is called. If the number increased then a new exception is detected and the predicate
returns
true.
|
Note
|
This predicate is designed for a specific use case with scope guards created on the stack. It is incompatible with C++20 coroutines and similar facilities (e.g. fibers and userspace context switching), where the thread of execution may be suspended after the predicate captures the number of uncaught exceptions and then resumed in a different context, where the number of uncaught exceptions has changed. Similarly, it is incompatible with usage patterns where the predicate is cached after construction and is invoked after the thread has left the scope where the predicate was constructed (e.g. when the predicate is stored as a class data member or a namespace-scope variable). |