error: lvalue required as left operand of assignmentfnc("something") = Obj
Author
My function fnc returns a X* Type object.
So can I use fnc("something") = Obj
if Obj is of type X* or XDerived*
I've already tried and compiler fired error saying.
Quote:Original post by nlbsNo.
My function fnc returns a X* Type object.
So can I use fnc("something") = Obj
Unless your function returns a reference to a pointer, you can't assign to its return value like this. So, for example:
X* &get(){ static X* internal; return internal;}get() = new X();
Author
Thanks fro that Information.
Hmm In method signature I can use.
Js::JType* &operator()(const string& key);
But what would I put in cpp
Js::JType* &Js::Object::operator()(const string& key){
fires Compilation errors.
Hmm In method signature I can use.
Js::JType* &operator()(const string& key);
But what would I put in cpp
Js::JType* &Js::Object::operator()(const string& key){
fires Compilation errors.
Author
jobject.cpp:37: error: invalid initialization of reference of type 'Js::JType*&' from expression of type 'Js::JType* const'for the following line
Js::JType* &Js::Object::operator()(const string& key){EDIT
Sorry the error is for a different reason
As I've already posted I am not deleting it.
I think &Js::Object::operator()(const string& key) doesn't causes the problem
overlooked the error message
Author
In that function I've return it->second.
it is of type Iterator (non-const Iterator) and on that line Its firing that above error.
Now from where it getting the const I am not able to understand.
it is an iterator to a stl map.
std::map<std::string, Js::JType*>
EDIT
However Casting it directly works
return (Js::JType* &)(it->second)
[Edited by - nlbs on November 5, 2008 9:29:52 AM]
it is of type Iterator (non-const Iterator) and on that line Its firing that above error.
jobject.cpp:37: error: invalid initialization of reference of type 'Js::JType*&' from expression of type 'Js::JType* const'Now from where it getting the const I am not able to understand.
it is an iterator to a stl map.
std::map<std::string, Js::JType*>
EDIT
However Casting it directly works
return (Js::JType* &)(it->second)
[Edited by - nlbs on November 5, 2008 9:29:52 AM]
You need to be extremely careful when casting, especially a C-style cast.
This compiles:
Can you post a minimal* example that exhibits the behaviour you are seeing?
* This means I should be able to copy and paste the code into my IDE and build it. No external headers etc.
This compiles:
#include <map>#include <string>#include <stdexcept>struct Type{};struct Example{ Type *& foo(const std::string &s) { std::map<std::string, Type *>::iterator it = map.find(s); if(it != map.end()) { return it->second; } else { throw std::runtime_error("blah"); } }private: std::map<std::string, Type *> map;};Can you post a minimal* example that exhibits the behaviour you are seeing?
* This means I should be able to copy and paste the code into my IDE and build it. No external headers etc.
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