boost::priority_queue help
Created a boost::priority_queue with my comparison operation defined. Here is how my priority_queue looks, boost::heap::priority_queue<myObject*, boost::heap::compare<myObjectPtrCompare> > max_heap; My comparison is defined as, struct myObjectPtrCompare{ bool operator()(const myObject* lhs, const myObject* rhs) const { return (lhs->getTime() < rhs->getTime()); }}; I have used it as, myObject* obj1 = static_cast<myObject*>(base1); 'base1' is an object of class 'myBase'(base class of myObject) myObject and getTime() within it used for comparision are defined as, class myObject : public myBase { Time getTime() const { return time; }... ...} Compiling this gives me this error, c:\Projects\pq_test.cpp(27): error C2662: 'void boost::heap::priority_queue<myObject*,boost::heap::compare<myObjectPtrCompare>,boost::parameter::void_,boost::parameter::void_,boost::parameter::void_>::push(myObject *const &)' : cannot convert 'this' pointer from 'const boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>,boost::parameter::void_,boost::parameter::void_,boost::parameter::void_>' to 'boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>,boost::parameter::void_,boost::parameter::void_,boost::parameter::void_> &'1> Conversion loses qualifiers Using Visual Studio 2013 C++. I understand that I am doing something wrong with const correctness, but I am not able to figure out what is wrong. Any help is appreciated. TIA!
AMDG On 12/08/2017 04:38 AM, Ram via Boost-users wrote:
<snip>
c:\Projects\pq_test.cpp(27): error C2662: 'void boost::heap::priority_queue<myObject*,boost::heap::compare<myObjectPtrCompare>>::push(myObject *const &)' : cannot convert 'this' pointer from 'const boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>>' to 'boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>> &'1> Conversion loses qualifiers
Using Visual Studio 2013 C++. I understand that I am doing something wrong with const correctness, but I am not able to figure out what is wrong. Any help is appreciated.
You're trying to push onto a const priority_queue. In Christ, Steven Watanabe
Yes thanks Steven! The queue was modified inside a const method of the class. I corrected it but now I get these warning(we treat them as errors). These are the warnings, 1> priority_queue_example.cpp 1>c:\Projects\lib\boost\boost\heap\detail\stable_heap.hpp(102): error C2220: warning treated as error - no 'object' file generated 1>c:\Projects\lib\boost\boost\heap\detail\stable_heap.hpp(102): warning C4100: 'rhs' : unreferenced formal parameter 1> c:\Projects\lib\boost\boost\heap\detail\stable_heap.hpp(102) : while compiling class template member function 'boost::heap::detail::size_ holder<false,size_t>::size_holder(const boost::heap::detail::size_holder<false,size_t> &)' 1> c:\Projects\lib\boost\boost\heap\detail\stable_heap.hpp(189) : see reference to function template instantiation 'boost::heap::detail::size_ holder<false,size_t>::size_holder(const boost::heap::detail::size_holder<false,size_t> &)' being compiled 1> c:\Projects\lib\boost\boost\heap\detail\stable_heap.hpp(151) : see reference to class template instantiation 'boost::heap::detail::size_holder<false,size_t>' being compiled 1> c:\Projects\lib\boost\boost\heap\priority_queue.hpp(65) : see reference to class template instantiation 'boost::heap::detail::heap_ base<T,myObjectPtrCompare,false,unsigned __int64,false>' being compiled 1> with 1> [ 1> T=myObject * 1> ] 1> c:\Projects\priority_queue_example.h(193) : see reference to class template instantiation 'boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>,boost::parameter::void_,boost:: parameter::void_,boost::parameter::void_>' being compiledcompare< ObjectPtrCompare>,boost::parameter::void_,boost::parameter::void My priority_queue is declared as, mutable boost::heap::priority_queue<myObject*, boost::heap::compare<myObjectPtrCompare>
hp;
Can you please help me fix this, I have been trying to for 2 days. Not sure what this means. This is my comparison class defined, struct myObjectPtrCompare { bool operator()(const myObject* lhs, const myObject* rhs) const { return (lhs->getProp() < rhs->getProp()); } }; Can you please help with this? I understand that 'rhs' is unused, but in my implementation, it is used but the warning is pointing to boost code. I don't understand it. Thanks! On Sat, Dec 9, 2017 at 9:56 AM, Steven Watanabe via Boost-users < boost-users@lists.boost.org> wrote:
AMDG
On 12/08/2017 04:38 AM, Ram via Boost-users wrote:
<snip>
c:\Projects\pq_test.cpp(27): error C2662: 'void boost::heap::priority_queue<myObject*,boost::heap:: compare<myObjectPtrCompare>>::push(myObject *const &)' : cannot convert 'this' pointer from 'const boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>>' to 'boost::heap::priority_queue<myObject *,boost::heap::compare<myObjectPtrCompare>> &'1> Conversion loses qualifiers
Using Visual Studio 2013 C++. I understand that I am doing something wrong with const correctness, but I am not able to figure out what is wrong. Any help is appreciated.
You're trying to push onto a const priority_queue.
In Christ, Steven Watanabe
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