Questions tagged [c++14]
C++14 is the version of C++ after C++11. This tag should be used (along with the [C++] tag) for questions about C++ features specific to C++14.
c++14
8,564
questions
0
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0
answers
13
views
How to include version information in a C++ project? [closed]
I wrote a C++ static library, and I want to add version information for it in a designated header. I'm working with C++14.
I'm contemplating on multiple approaches:
Adding it as macros:
#pragma once
...
- 1
-1
votes
0
answers
52
views
Error C2059 syntax error: '__declspec(dllexport)' only when return type is a pointer [duplicate]
I need to create a DLL wrapper around a function that returns unsigned char*. For that I declare the wrapping function in wrapper.h as:
extern "C" unsigned char* __declspec(dllexport) fn();
...
- 15
0
votes
1
answer
68
views
Fixing boost::optional undefined type error
I was trying to create a bidirectional tree-like structure, so Ive ended up with the following struct`s:
template<typename T>
struct Node
{
T value;
std::vector<...
- 25
12
votes
3
answers
1k
views
Is it legal to initialize an array via a functor which takes the array itself as a parameter by reference?
In the question Idiom for initializing an std::array using a generator function taking the index?,which basically asks how one can initialize an array of an arbitrary type which is not necessarily ...
- 4,051
0
votes
0
answers
56
views
Why doesn't std::array<T,N>::operator[] return an rvalue reference for rvalue object? [duplicate]
std::array<T,N>::operator[] always returns an lvalue reference (const if needed), but what can possibly be the use of a line of code like this, which is valid C++?
std::array<int,1>{1}[0] =...
- 26.6k
0
votes
0
answers
20
views
gRPC 1.47.4 vs2017 compilation errors
In my company we try to create packages of gRPC and all dependencies in our private conan repository. Currently we stuck with gcc6.4.0 and VS2017. I had currently created packages for these ...
- 1
2
votes
3
answers
152
views
In C++, compared to final or not virtual function, what is the advantage of CRTP?
I'm new to learning modern C++ programming. I have read many blogs and questions but haven't found the answer of this question. In C++, compared to final or not virtual function, what is the advantage ...
- 33
0
votes
0
answers
18
views
Confused about AUTOSAR AP accessing to method result
AUTOSAR AP defines Request&Response approachs for users, its format just like this
ara::core::Future<Output> user_defined_method(Input in)
As you see, AUTOSAR AP uses Future to wrap output ...
- 703
1
vote
2
answers
98
views
Specialize a method template with type parameter with a non-type one
I'm trying to implement a class template with static member functions that can handle different types. My code looks like this (very simplified example):
#include <array>
struct Foo {
...
- 5,568
5
votes
1
answer
179
views
Compile result different in GCC 13.1 and GCC 13.2 constructing a string
I have the following code that compiles fine on GCC 13.2. Colleagues can't compile it on GCC 13.1. The new version compiles fine even with -Wall -Wextra. I assume that GCC 13.2 is better and more ...
- 57.4k
4
votes
3
answers
187
views
free() on result of placement new?
I'm trying to understand whether it's valid to call free() on the result of placement new in a buffer allocated by malloc().
Consider the following. Does this code exhibit any undefined behavior?
(...
- 349
0
votes
0
answers
39
views
How to use boost log in visual studio 2015 and build platform is v140
I have added all the dependencies but after adding it i am getting some linking error. I am using visual studio 2015 buildtool v140 , platform v8.1 and platform win32.
I have added the necessary ...
- 21
1
vote
1
answer
80
views
How to print the line number of the caller function from a template function?
I am implementing a log function which logs along with line number of the code. The snippet of the code as follows:
#include <iostream>
using namespace std;
char m_buffer[500];
template<...
- 311
0
votes
2
answers
68
views
Seamlessly using maps with different comparators
I was using an alias to refer to one of two maps:
map<int, int> & map_alias = use_map_a ? map_a : map_b;
but then changed map_b to use std::greater as its comparator (instead of the default ...
- 1
0
votes
2
answers
109
views
Code won't continue if i use 2 as the input
If i input number 2 for std::cin >> menu;, the code after std::cin >> menu; won't execute.
At first, i think the problem is in the function, but the code haven't even go to the switch (i ...
-1
votes
2
answers
63
views
Polymorphic behavior of derived class objects in C++ STL list [duplicate]
I am storing objects of base and derives classes (Account, StudentAccount, EmployeeAccount) in an STL list and process them with STL Iterator. The dynamic polymorphic behavior of objects is not ...
0
votes
1
answer
56
views
adding pointers to keys in map in map
struct ndptr_t {
const pnode *ptr;
ndptr_t(const pnode* _p = nullptr) : ptr(_p) {}
~ndptr_t() {
// if no ndptr_t used outside map nid, clear nid
}
};
static std::map<...
- 63
0
votes
1
answer
35
views
initialization of boost::flyweights::intermodule_holder fails with interprocess_exception and permission denied
I've no clue why this would fail.
The shared_memory_object should be unique as it is only accessed from within the same process.
The current directory is writable and so is $TMPDIR and so is /tmp/
...
- 495
0
votes
1
answer
68
views
Reusable ::testing::Values generator in gtest
I have a piece of software (c++) thats tested excessively with googletest.
There are a lot of INSTANTIATE_TEST_SUITE_P calls.
There is a particular value generator that I'd like to reuse, something ...
- 452
4
votes
1
answer
178
views
Why is this trivial code requiring exception handling
We are currently working on an embedded system where C++ exceptions cannot be used and thus their support is deactivated in the compiler/linker settings. In this project, we get a IAR-linker error for ...
- 728
0
votes
1
answer
101
views
Tree with std::unique_ptr. Reference cannot be bound to dereferenced null pointer in well-defined C++ code
I am trying to write a tree data structure with unique_ptr but I ma getting following warning while printing the Tree:
struct Node {
int data_{0};
std::unique_ptr<Node> left_{nullptr};
...
- 11
0
votes
0
answers
52
views
CURL do not free memory inside a thread without a active host
I need to call several POST requests every second with an image and I can't wait for any response When my host is active everything works good. But when the host is offline, the memory increase fast ...
0
votes
0
answers
28
views
error: ‘CV_WRAP_FILE_PATH’ has not been declared
when I add #include “opencv2/objdetect.hpp” , there is a wrong
“/usr/include/opencv2/objdetect/face.hpp:85:47: error: ‘CV_WRAP_FILE_PATH’ has not been declared
85 | CV_WRAP static Ptr create(...
-6
votes
3
answers
158
views
Is writing else statement at the last mandatory in if-else ladder in C++?
I have always seen that at the end of an if-else ladder in C++, the bottom else statement is always present.
if (condition1) {
doA();
} else if (condition2) {
doB();
} else if (condition3) {
doC(...
1
vote
1
answer
36
views
Finding a sequence in a row of matrix using lower_bound
I needed to write a function which will sort the rows of a matrix (vector<vector<int>>) by a specified criterion. The criterion is that a row is said to come first if its biggest element ...
- 33
-2
votes
1
answer
216
views
Can I use MISRA-2023 with C++14?
I would like to follow the MISRA C++:2023 coding guideline. But it targets C++17, while the code and compiler follow C++14.
The document reads:
The guidelines within this document target C++17, and ...
- 926
0
votes
1
answer
111
views
Save compressed DICOM image without having to temporally save uncompressed DICOM
I have a DicomInterface class that inherits from DcmDataset class. After setting the DICOM tags, I want to save the DICOM image with JPEG Process 14 transfer syntax. If I first save the DICOM file ...
0
votes
1
answer
97
views
Explanation for extra move constructor call
I will straightaway head to the code and explain what I'm trying to understand here.
class MyInt
{
unique_ptr<int> ptr;
public:
MyInt(int val)
{
cout <&...
- 437
3
votes
1
answer
90
views
Can I use std::align to verify the alignment of a given pointer?
The following function template tries to locate an object in an array of bytes.
We may assume that the argument buffer "usually" holds an object of the given type, but I need a diagnostic (...
- 1,429
0
votes
0
answers
51
views
The implementation of tbb::parallel_for gives a sigsev segmentation error
I was compiling a program named autoremesher on Ubuntu 22.04. It's an open source project, and I was requested to remove it's GUI. That I did and removed it's dependency from QT framework, except for ...
1
vote
2
answers
108
views
Why can't I use templates members in its specialization?
Here's my code:
#include <iostream>
template <typename T>
struct Foo
{
public:
T DataMember;
};
template<>
struct Foo<int>
{
public:
void bar()
{
std::...
0
votes
1
answer
50
views
Is there a way to implement std::regular_invocable as a type_trait style function in c++11/c++14?
I'm currently working on an Arduino "gameboy" style project where I'm trying to make a library that will work like a game engine. In the Arduino IDE there is no c++ STL when using an AVR ...
0
votes
0
answers
54
views
The instruction at 0x00007FF697F8AE43 referenced memory at OxFFFFFFFFFFFFFFFF. The memory could not be read
I'm writing a programming lab and I have this error, I don't know how to solve this, please help
bug
the program crashes when I select item 10 and information from the file is not deleted afterward
...
2
votes
1
answer
106
views
operator delete after both operator new and placement new?
Suppose I want to put an object on the "heap", but I need to have some additional memory allocated after it.
My understanding is that the following would be a standard-compliant way of doing ...
- 349
0
votes
1
answer
107
views
module "QtNetwork" is not installed
Here is the complete content of my .pro file (I have specified to add the network module):
QT += quick virtualkeyboard network
# You can make your code fail to compile if it uses deprecated APIs.
# ...
- 1
0
votes
1
answer
68
views
How can std::unique_ptr apply EBO on closure?
#include <memory>
#include <cstdio>
int main(){
auto x1 = [](int *p){ delete(p); };
auto ptr = std::unique_ptr<int, decltype(x1)>(new int{1},x1);
printf("%zu\n&...
- 33
0
votes
2
answers
77
views
auto in if clause - the way to define parameters inside if [duplicate]
I want to define a parameter inside if . for example
if(MyDataPtr && auto* InfoPtr = MyDataPtr ->extractInfo())
And gen compilation error Expected ')'
Is it impossible? or what ca be done? ...
- 10.1k
1
vote
0
answers
122
views
How to undefine and redefine a macro in C++?
I have a macro in the existing part of project that I want to suppress for my includes. The existing macro is defined like this:
#define NAME _T(MYCONST("Name"))
However In ...
- 440
0
votes
1
answer
69
views
how to overload unique_ptr in a class . i am getting compilation error [duplicate]
std::unique_ptr<Manager>& checkManager(std::unique_ptr<Manager> &p1)
{
if(p1 && p1->getName().find("Manager") != std::string::npos ){
std::cout<&...
- 160
5
votes
3
answers
129
views
C++ Fundamentals: Template operator- overloading Failed - "template argument deduction/substitution failed"
I have been trying to write my own vector class to better understand C++ templates and iterators, but have been stuck with this error for a while and would really appreciate the help.
The code fails ...
- 492
-2
votes
1
answer
157
views
How to write a google mock matcher to match a void pointer argument?
I have a function that takes a const void* that I'm mocking. I want to have matchers based on the value of pointee that's being passed into the function.
For example:
#include <vector>
#include &...
- 3,447
1
vote
1
answer
105
views
Pre-C++17 replacement for CTAD?
(Or: "How to store the return value of a template-argument-deduced function where auto is not allowed")
I'm working on a generic C++ framework made up of several class templates
that allow ...
- 1,429
2
votes
0
answers
64
views
C++ constexpr compiles too fast [duplicate]
When I compile a program including:
#include <iostream>
using namespace std;
constexpr int fib_c(int n)
{
if (n<=1) return n;
return fib_c(n-1)+fib_c(n-2);
}
int main()
{
...
- 21
0
votes
1
answer
132
views
error: implicit instantiation of undefined template 'std::tuple_element<0, std::tuple<std::string, int> &>' [duplicate]
I have checked out the related posts to this error and wasn't able to use those solutions to solve my problem. So i have this code that attempts to dynamically create a tuple by converting stringified ...
- 41
0
votes
0
answers
56
views
error: no matching function for call to 'get<i>(std::tuple<int, int>&)' [duplicate]
I'm quiet new to C++, so I can't really figure out the issue. I really hope someone can help me.
Whenever I run a loop and try to set a tuple's value inside of that loop, I get an error saying:
error:...
- 41
1
vote
1
answer
278
views
error: no matching function for call to 'std::tuple<std::vector<int, std::allocator<int> >&, int>::tuple()'
Hey I normally work with Javascript and dart but I've been required to write some code in C++ for some project so I've been facing a lot of issues while writing it. I have this error that I've been ...
- 41
0
votes
2
answers
115
views
How to lazily instantiate a functor argument passed in a function when calling it under some condition in C++14?
Assume that I have a function that abstracts some error-handling logic, it has argument which is a functor. Inside it, it calls this functor conditionally.
The function looks like this:
void ...
- 305
5
votes
2
answers
233
views
Implement Non Copyable Non Moveable wrapper for map/vector etc
I want to write a wrapper over the STL containers like map, vector, unordered map etc. that do not have copy or move constructors. There are a few approaches that I can think of, but none are nice:
...
- 8,491
0
votes
0
answers
47
views
Implementation propagation_const in prio C++17 version
It is the following example
#include <iostream>
#include <memory>
class B{
public:
void foo() const{
std::cout << "foo const" << std::endl;
}
...
- 855
0
votes
0
answers
87
views
C++ library added but still unresolved external symbol error
Inside my c++ project I have a folder: "include" with 3 files:
Framework.h , FrameworkRelease_x86.dll ,FrameworkRelease_x86.lib .
I included them as it was stated in microsoft documentation:
...
- 13