Use this tag for questions related to the 'using' keyword in C++.
Questions tagged [using-declaration]
164 questions
2
votes
2 answers
"Using declaration" not working in RADStudio 2010
I'm deriving a new class from the VCL TStream class:
// A stream based on a temporary file, deleted when the stream is closed
class TTempFileStream : public TStream
{
...
public:
using TStream::Seek;
__int64 __fastcall Seek(const __int64…
Roddy
- 66,617
- 42
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1
vote
1 answer
C++ `using` keyword vs derived class
We have a templated type Foo.
In the codebase, it's 99% instantiated with a couple of types, and I would like to use a distinct name for those cases.
What are the pros/cons of the using keyword (using FooA = Foo) vs declaring an empty derived…
maattdd
- 181
- 2
- 6
1
vote
0 answers
How to use "using static" with generic classes?
C# has an using static directive since C# 6.0 which is allows to includes more specific things (like classes, interfaces etc.) than namespaces. Well, I tried to include generic type class (System.Collections.Generic.List to be clear). I used…
Ufuk Can İşbildi
- 157
- 1
- 10
1
vote
1 answer
Does the using declaration allow for incomplete types in all cases?
I'm a bit confused about the implications of the using declaration. The keyword implies that a new type is merely declared. This would allow for incomplete types. However, in some cases it is also a definition, no? Compare the following…
glades
- 3,778
- 1
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1
vote
1 answer
Default argument for template not working
I have a chain of nested templated using declarations. It looks something like this:
template
class Foo {
public:
Foo() : value{0} {};
template
Seymore Glass
- 53
- 1
- 4
1
vote
1 answer
Observation (check): same member function name, different signature, one as virtual member
I'm afraid this is not possible:
class A {
public:
A(){}
virtual string s() = 0
string s(int i) {
auto j = this->s();
... modify j ...
return j;
};
class B: public…
stustd
- 303
- 1
- 10
1
vote
0 answers
Issues with C++ namespace across file and using directive
Here are a demo code from C++ primer plus about using using-directive and using-declaration across header files and cpp files, I've made some modification to remove the using declarations in other function to have cout and end and the code…
lyu.l
- 282
- 3
- 8
1
vote
2 answers
Extremely basic question about namespaces in c++
using namespace X;
cout << var;
using Y::var;
cout << var;
So say I have a namespace X and a namespace Y that both contain a variable of type int called var. When I say using namespace X; what I imagine happening is if I use some…
jaylse2
- 71
- 4
1
vote
1 answer
Using syntax to expose base class alias templates and variable templates in derived class?
Consider a base template class and a derived template class in a heavy template metaprogramming context (simplified here for readability and to focus on the problem).
template
struct base {
using type = T;
static constexpr int…
Vincent
- 57,703
- 61
- 205
- 388
1
vote
1 answer
C++ inheritance overloads functions with different parameters
I am working on a project which uses class inheritance and requires lots of overloads in both the base and derived class, I have simplified the code, but I wouldn't want to unnecessarily copy and paste since that's supposed to be what inheritance is…
MaximV
- 155
- 11
1
vote
1 answer
the overload resolution of using base member function introduced into derived class
According to some quotes in standard:
[over.match.funcs]/4
[...] For non-conversion functions introduced by a using-declaration into a derived class, the function is considered to be a member of the derived class for the purpose of defining the…
xmh0511
- 7,010
- 1
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1
vote
2 answers
Function-definition in class requires same function in other class : compilation error
I have an enum class "Suit" and defined a function "string to_string(Suit e)"
In another class, "Card", I have a member variable "my_Suit" and a member-function "to_string". This function calls the function "to_string" with "my_Suit" as a…
J. Adriaenssens
- 71
- 6
1
vote
3 answers
C++ "using" declaration in Visual Studio 2008
I am trying to use google protobuf and they have the following example:
using google::protobuf;
protobuf::RpcChannel* channel;
protobuf::RpcController* controller;
SearchService* service;
SearchRequest request;
SearchResponse response;
void…
beepboopbeep
1
vote
2 answers
How can I typedef a bound a member method and then use that type as a template parameter?
I'm trying to bind a method of a class and to pass it as a template parameter to a different class. This type needs to be used in multiple methods, so I tried using a using clause in the class (struct base below).
However, I'm not really able to get…
Avi Ginsburg
- 10,323
- 3
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1
vote
2 answers
using declaration: one more bug of gcc and clang?
Why do gcc HEAD 10.0.0 20190 and Clang HEAD 9.0.0 both reject this program?
#include
void g( int x )
{
std::cout << "Hello g( " << x << " )\n";
}
template
void g()
{
std::cout << "Hello g( " << N << "…
Vlad from Moscow
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