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Update C++ Exceptions programming guide

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PB 2022-11-01 18:19:17 +01:00 • committed by Vadim Zeitlin
parent 6115692265
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docs/doxygen/overviews/exceptions.h
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@ -12,17 +12,12 @@
@tableofcontents
wxWidgets had been started long before the exceptions were introduced in C++ so
it is not very surprising that it is not built around using them as some more
modern C++ libraries are. For instance, the library doesn't throw exceptions to
signal about the errors. Moreover, up to (and including) the version 2.4 of
wxWidgets, even using the exceptions in the user code was dangerous because the
library code wasn't exception-safe and so an exception propagating through it
could result in memory and/or resource leaks, and also not very convenient.
it is not very surprising that it is not built around using them, i.e.
the library doesn't throw exceptions to signal about the errors.
However the recent wxWidgets versions are exception-friendly. This means that
while the library still doesn't use the exceptions by itself, it should be now
safe to use the exceptions in the user code and the library tries to help you
with this.
However it is exception-friendly. This means that while the library doesn't
use the exceptions by itself, it should be now safe to use the exceptions in
the user code and the library tries to help you with this.
@ -97,17 +92,6 @@ void TestNewDocument()
}
@endcode
Unfortunately, by default this example only works when using a C++11 compiler
because the exception can't be safely propagated back to the code handling it
in @c TestNewDocument() through the system event dispatch functions which are
not compatible with C++ exceptions and needs to be stored by wxWidgets when it
is first caught and rethrown later, when it is safe to do it. And such storing
and rethrowing of exceptions is only possible in C++11, so while everything
just works if you do use C++11, there is an extra step if you are using C++98:
In this case you need to override wxApp::StoreCurrentException() and
wxApp::RethrowStoredException() to help wxWidgets to do this, please see the
documentation of these functions for more details.
@section overview_exceptions_tech Technicalities