Re: [boost] [inspect] exceptions (FW: [Boost-users] no exceptions)

24 Mar 2011

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Message du 23/03/11 22:13
De : "Joaquin M Lopez Munoz" 
A : boost@lists.boost.org
Copie à : 
Objet : Re: [boost] [inspect] exceptions (FW: [Boost-users] no exceptions)
Vicente BOTET  wanadoo.fr> writes:
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On Tue, Mar 22, 2011 at 12:16 PM, Krzysztof Czainski
<1czajnik  gmail.com> wrote:
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What about boost/detail/no_exceptions_support.hpp?
[...]
I'm wonderyn if the following wouldn't be more natural
void foo() {
BOOST_TRY {
...
} BOOST_CATCH(const std::bad_alloc&) {
...
BOOST_RETHROW
} BOOST_CATCH(const std::exception& e) {
...
} BOOST_CATCH_ALL {
...
}
}
If you refer to why BOOST_CATCH_END is needed in the original
formulation, consider the following:
if(so)
BOOST_TRY{
foo();
}
BOOST_CATCH(const std::exception& e){
bar();
BOOST_RETHROW
}
else
baz();
This, using your variation, expands to
if(so)
if (true){
foo();
}
else if (false){
bar();
}
else
baz();
which is equivalent to (note the braces)
if(so){
if (true){
foo();
}
else if (false){
bar();
}
else{
baz();
}
}
which is clearly not the intention.
Yes I see. This is why I added BOOST_CAT_ALL, but the its use can not be forced and as your example shows can have dramatic effects.

Thanks,
Vicente