Hello:
I just started using some boost today. I am trying to use a non-static
member function as the deleter in a shared_ptr. I was looking at the
source code and I don't think it is supported. This is what I had:
shared_ptr<Environment> environment(Environment::createEnvironment(),
Environment::terminateEnvironment);
string userName = "monkey_bottoms";
string password = "blahblahblah"
shared_ptr<Connection> connection(
environment->createConnection(
userName,
password),
&Environment::terminateConnection);
This didn't work at all! When I looked at the source I saw why. Note
that Environment::terminateConnection is a static method. However,
this source works fine for the static Environment::createEnvironment
method.
I am working in Visual Studio 8 with the OCCI. For the time being, I
have made a temporary solution. I am hoping someone can help me find a
less customized solution. Plus, I am thinking having a pointer to an
object that I am trying to manage kind of defeats the point. Here you
go:
#include "occi.h"
#include
#include <string>
#include <functional>
// retarded temporary solution
template
class call_redirect_t : public std::unary_function
{
TCLASS * instance; // barf I have a pointer to a managed resource!
TRETURN (TCLASS::*func) (TARG);
public:
call_redirect_t(TCLASS * instance, TRETURN (TCLASS::*func) (TARG))
: instance(instance),
func(func)
{
}
TRETURN operator()(TARG arg)
{
return (instance->*func)(arg);
}
};
// convenience function
template
call_redirect_t call_redirect(TCLASS *
instance, TRETURN (TCLASS::*func)(TARG))
{
return call_redirect_t(instance, func);
}
int main(int argc, char * argv[])
{
// lazy
using namespace std;
using namespace oracle::occi;
using namespace boost;
shared_ptr<Environment> environment(
Environment::createEnvironment(), // gets Environment *
Environment::terminateEnvironment); // static method
string userName = "flipflop";
string password = "memoryrizor";
shared_ptr<Connection> connection(
environment->createConnection(userName, password), // gets Connection *
call_redirect(
environment.get(), // pull the pointer out; instant poo
&Environment::terminateConnection) // non-static method
);
}
Well, now that I think about it; since the temporary call_redirect
will only exist in the scope of the shared_ptr (who handles my
resource) it doesn't matter that I let it go, and parameter evaluation
order is not an issue.
Take a look at the operator() in call_redirect_t. I had to put
parenthesis around:
(instance->*func)
I am think I have forgotten the syntax. Hmph. Weep, I am not perfect.
Thanks for any input, folks.
Travis Parks
