Re: How to make this exception-safe
On 19 Nov, 22:25, Ulrich Eckhardt <eckha...@satorlaser.com> wrote:
Triple-DES wrote:
Consider the following code:
#include <vector>
struct C {
explicit C(int) {} // may throw
private:
C(const C&);
C& operator=(const C&);
};
struct V {
V() {
// may leak if push_back or C::C(int) throws
v_.push_back( new C(2) );
v_.push_back( new C(1) );
v_.push_back( new C(3) );
}
Use vector's reserve() function. Alternatively, use a temporary auto_ptr:
auto_ptr<C> p(new C(2));
v_.push_back(p.get());
p.release();
Note that you must not use the returnvalue of p.release(), because then
you
first release ownership while the vector is reallocated. That said, this
still won't work, because the destructor of V will not be called when the
constructor throws, but the destructor of vector<> will not delete the
elements it points to. Therefore: try, catch, rethrow.
My solution does not contain any try/catch, and it shouldn't leak (At
least no one has been able to prove it so far).
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