Given the following definition:
std::vector< std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> > >
PairsVector;
What is the best way to insert objects into the vector (without creating
them separately before inserting them)? I tried the following, but the
compiler complains that it cannot find a matching constructor:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( new Class1( NULL ),
new Class2( NULL ) ) );
On the other hand, this does compile:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( boost::shared_p tr<Class1>(new Class1( NULL )),
boost::shared_p tr<Class2>(new Class2( NULL )) ) );
Why won't the pair<> constructor accept the raw pointers and simply assign
them to the shared_ptr's?
- Dennis
4  3417 
Dennis Jones wrote: Given the following definition:
std::vector< std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> > >
PairsVector;
What is the best way to insert objects into the vector (without
creating them separately before inserting them)? I tried the
following, but the compiler complains that it cannot find a matching
constructor:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( new Class1( NULL ),
new Class2( NULL ) ) );
On the other hand, this does compile:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( boost::shared_p tr<Class1>(new Class1(
NULL )),
boost::shared_p tr<Class2>(new Class2( NULL )) ) );
Why won't the pair<> constructor accept the raw pointers and simply
assign them to the shared_ptr's?
Could it be that 'shared_ptr's constructor is _explicit_?
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Dennis Jones wrote: Given the following definition:
std::vector< std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> > >
PairsVector;
What is the best way to insert objects into the vector (without
creating them separately before inserting them)? I tried the
following, but the compiler complains that it cannot find a matching
constructor:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( new Class1( NULL ),
new Class2( NULL ) ) );
On the other hand, this does compile:
PairsVector.pus h_back( std::pair< boost::shared_p tr<Class1>,
boost::shared_p tr<Class2> >( boost::shared_p tr<Class1>(new Class1(
NULL )),
boost::shared_p tr<Class2>(new Class2( NULL )) ) );
Why won't the pair<> constructor accept the raw pointers and simply
assign them to the shared_ptr's?
Because boost::shared_p tr's constructor is declared as 'explicit' to avoid
the dangers of implicit conversion. Try:
typedef boost::shared_p tr<Class1> tPtr1;
typedef boost::shared_p tr<Class2> tPtr2;
typedef std::pair<tPtr1 ,tPtr2> tPtrPair;
typedef std::vector< tPtrPair > tPtrPairVector;
tPtrPairVector PtrPairVector;
PtrPairVector.p ush_back( tPtrPair( tPtr1( new Class1(NULL) )
, tPtr2( new Class2(NULL) )
)
);
If you find yourself doing this a lot, it may be worth adding a
static Ptr function to your Class1 and Class2 classes.
class Class1
{
....
Class1( int aInt ).... // make private
public:
typedef boost::shared_p tr<Class1> tPtr;
static tPtr Ptr( int aInt ){ return tPtr( new Class1( aInt ); }
};
Ditto for Class2,
Then the push_back above is called like:
PtrPairVector.p ushBack( tPtrPair( Class1::Ptr(NUL L), Class2::Ptr(NUL L) ) );
Jeff Flinn
"Victor Bazarov" <v.********@com Acast.net> wrote in message
news:e1******** **@news.datemas .de... Why won't the pair<> constructor accept the raw pointers and simply
assign them to the shared_ptr's?
Could it be that 'shared_ptr's constructor is _explicit_?
Duh, of course!!! I know what an explicit constructor is, but I've only
used one in my own classes once before, so it never even entered my mind.
Thank you!
- Dennis
Dennis Jones wrote:
Why won't the pair<> constructor accept the raw pointers and simply assign
them to the shared_ptr's?
Because the shared_ptr constructor that takes a raw pointer is explicit.
It won't be called for an implicit conversion.
--
Pete Becker
Roundhouse Consulting, Ltd. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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