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Not all exceptions can be caught. Quoting from \[except.handle\], p13 of [N3000|http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n3000.pdf], the current Working Draft of the C+\+ standard: |
Exceptions thrown in destructors of objects with static storage duration or in constructors of namespace-scope objects with static storage duration are not caught by a function-try-block on
main(). Exceptions thrown in destructors of objects with thread storage duration or in constructors of namespace-scope objects with thread storage duration are not caught by a function-try-block on the initial function of the thread.
To illustrate using an example:
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struct Foo {
Foo(); // may throw
~Foo(); // may throw
};
Foo A;
void bar() {
static Foo B;
}
int main()
try {
bar();
// other executable statements
}
catch(...) {
// will catch exceptions thrown from bar() and
// any other executable statements in the try
// block above
// IMPORTANT: will not catch exceptions thrown
// from the constructor of the global object A
// or those from the destructor of the static
// local object B defined in bar()
}
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Thus, it is important to prevent constructors and destructors of objects with static storage duration to throw exceptions.