[boost] FW: [Boost-users] Suggestion for boost`s smart pointers

29 Nov 2006

      Hi,

Please see the following email about additional template parameters for
scoped_ptr. The quick hack I wrote for it is below (I've used this in
previous project as well). I think it would be very useful to many users
and wouldn't change any source using scoped_ptr.

Thanks,

Sohail
====
I've been thinking something like (just something I hacked together just
now). Not sure if there is a nicer way.

#include <string>
#include <cstdio>
#include <iostream>

template<typename T>
struct DeletingDeleter
{
	DeletingDeleter(T * p)
        {
            delete p;
            std::cout << "DeletingDeleter" << std::endl;
        }
};

struct FileCloser
{
    FileCloser(FILE * f)
    {
        std::cout << "Closing file" << std::endl;
        fclose(f);
    }
};

template<typename T, typename Deleter=DeletingDeleter<T> >
struct scoped_ptr 
{
    scoped_ptr():p_(0){}
    scoped_ptr(T * p):p_(p){}
    ~scoped_ptr()
    {
        Deleter d(p_);
    }
    T * get() {return p_;}
    // regular stuff
private:
    T * p_;
};

typedef scoped_ptr<FILE,FileCloser> file_ptr;

int main()
{
	  scoped_ptr<int> a; // maintain old interface
        scoped_ptr<int> b(new int(5));
        file_ptr p(fopen("myfile.txt","w"));
        fprintf(p.get(),"Hello world!\n");
}
...
-----Original Message-----
From: boost-users-bounces@lists.boost.org 
[mailto:boost-users-bounces@lists.boost.org] On Behalf Of David Klein
Sent: Tuesday, November 28, 2006 4:55 PM
To: boost-users@lists.boost.org
Subject: Re: [Boost-users] Suggestion for boost`s smart pointers
Sohail Somani wrote:
...
...
-----Original Message-----
From: boost-users-bounces@lists.boost.org 
[mailto:boost-users-bounces@lists.boost.org] On Behalf Of 
David Klein
Sohail Somani wrote:
...
...
-----Original Message-----
From: boost-users-bounces@lists.boost.org 
[mailto:boost-users-bounces@lists.boost.org] On Behalf 
Of mark cox
wow, this seems like a great idea, a scoped_ptr with deleter 
would be v.useful.
mark
I've been thinking something like (just something I hacked
together just
...
now). Not sure if there is a nicer way.
[snip]
...
+1 vote for this idea :)
i actually kind of did this for my current project,
because i needed a custom deleter for scoped_ptr,
when shared_ptr was to much overhead...
As did I, but it was not for performance but for readability. Shared
pointers mean... Shared. Scoped don't.
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yep exactly,
thatswhy i "ripped" scoped_ptr out of boost and added my 
custom_deleter 
stuff.
(i only *thought* about shared_ptr to do the job)
so are there any objections about adding this feature to scoped_ptr?
--
regards dave
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