56 questions
7
votes
1
answer
463
views
Is const T& effectively the same as T&& with std::forward for rvalue argument when be passed into another function?
Say I have a const T& version:
template <typename T>
void yetAnotherFunc( const T &input ) {
// do something...
}
template <typename T>
void myFunc( const T &input ) {
...
- 2,659
0
votes
1
answer
99
views
Why const reference is called and not rvalue reference and how std::move works? [duplicate]
#include <iostream>
void bar(std::string& s) { std::cout << "ref" << std::endl;}
void bar(const std::string& s) { std::cout << "const ref" << ...
- 9
3
votes
1
answer
891
views
How to avoid clang-tidy warning when passing shared_ptr to thread function?
I have C++ code that looks (simplified) like this:
#include <unistd.h>
#include <iostream>
#include <memory>
#include <string>
#include <thread>
std::thread the_thread;
...
- 6,881
0
votes
2
answers
289
views
Weird behavior with std::string reference class member
Given this code:
#include <iostream>
class Foo {
public:
Foo(const std::string& label) : label_(label) {}
void print() {
std::cout << label_;
}...
- 20.7k
2
votes
2
answers
256
views
Why does the "in" keyword allow mutation of properties C#?
I am currently working on a function where an object (of self written type Catalog) is passed and shall not be mutated / changed in the called function. Here a quick example.
public override bool ...
- 474
2
votes
2
answers
187
views
C++ struct as function argument vs. multiple const ref parameters vs. C++ core guidelines vs. performance?
I'm currently trying to decide whether to "structify" a rather long parameter set:
void fooCopy1(std::string const& source, std::string const& destination, std::string const& ...
- 39.3k
0
votes
1
answer
39
views
Is relying on the const-ness of arguments bind to const& parameters a recipe for thread un-safety?
I was just saw code like this
/* whatever */ foo(std::string const& s) {
// stuff
auto L = s.length();
int i{/* init based on L */};
while (i < L) {
// do other stuff and maybe
+...
- 30.1k
0
votes
3
answers
1k
views
Multiple functions with the same name but their parameters are either constant or received by value or by reference
The title is a bit lengthy, but it's best explained by an example:
Suppose we have the following functions in C++:
void SomeFunction(int num) { //1
}
void SomeFunction(int& num) { //2
}
void ...
- 23
-1
votes
2
answers
358
views
Is there any realistic use case for passing pointers by constant reference rather than by value?
Since a reference (some-type&) behaves as a constant pointer (some-type * const), passing an argument via a "constant reference to pointer" parameter (some-type * const&) seems a bit ...
- 30.1k
1
vote
1
answer
153
views
(C++) Using multiple operator overloads with const reference parameters [duplicate]
I have been working on a matrix class and I have recently learnt about passing const references to operator overloads so that I can have multiple of them on the same line. The problem I encountered is ...
2
votes
1
answer
219
views
C++20 : Memory allocation of literal initialization of const references
I am trying to optimize for speed of execution a piece of code using the factory design pattern.
The factory will produce many objects of a class having some members that are constant throughtout the ...
- 75
0
votes
0
answers
33
views
Are temporaries const? Pass by const reference [duplicate]
#include <iostream>
using namespace std;
void f(const int& x)
{
}
int g()
{
int x = 0;
return x;
}
int main() {
f(g());
}
If i remove the const from f it doesnt work;
What ...
- 39
2
votes
2
answers
1k
views
Pass-by-value and std::move vs forwarding reference
I encounter the pass by value and move idiom quite often:
struct Test
{
Test(std::string str_) : str{std::move(str_)} {}
std::string str;
};
But it seems to me that passing by either const ...
- 1,976
0
votes
1
answer
643
views
Using find_if with a vector of pointers: How to pass pointer by const reference to lambda?
In the following code I try to compare a vector of pointers via find_if and determine which contains a member a == 5 (in this case both of course, but it shows my case). However it doesn't compile.
#...
- 5,344
3
votes
1
answer
444
views
Why does C++ give preference to rvalue reference over const reference while function call? [duplicate]
So I wrote a code in C++ 11
#include <iostream>
using namespace std;
void print (int &&a)
{
cout<<"rval ref";
}
void print (const int& a)
{
cout<<&...
- 39