Recent questions tagged C++

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c++ - When are global variables actually considered good/recommended practice?

I've been reading a lot about why global variables are bad and why they should not be used. And yet ... ? Are global variables really needed? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Proper way to close a blocking UDP socket

I have a C++ object that creates a thread to read from a blocking UDP socket: mRunning.store(true); ... be cross-platform OSX/Linux/Windows) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Correct way to pause & resume an std::thread

I am using an std::thread in my C++ code to constantly poll for some data & add it to a buffer. I use ... and just play/pause it when required ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why can't we create an instance of an abstract class?

I found in many places that : An Abstract Class is a class which is supposed to be used as a base class. ... an instance of an abstract class? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why does libstdc++ store std::tuple elements in reverse order?

According to http://flamingdangerzone.com/cxx11/2012/07/06/optimal-tuple-i.html, with regards to std::tuple.. ... tuple ordering for any reason? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Will a reference bound to a function parameter prolong the lifetime of that temporary?

I have this code (simplified version): const int& function( const int& param ) { return param; } const ... temporary passed as the parameter? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is there any way of stopping _popen opening a dos window?

I am using _popen to start a process to run a command and gather the output This is my c++ code: ... currently does at the _popen statement)? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is this a singular iterator and, if so, can I compare it to another one?

I always thought that a "singular" iterator was one that has been default-initialised, and these could serve as ... is totally illegal. Is it? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to join in a WMI Query (WQL)

I want to get the serial number of the boot-harddisk via a WQL query. The boot-partition can be retrieved ... does it work with INNER JOIN? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - std::function -> function pointer

Here is a code: #include <functional> using namespace std::tr1; typedef void(*fp)(void); void foo(void) { } ... to solve the problem. Thank you. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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277 views

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c++ - C++98/03 std::is_constructible implementation

The base components of my hobby library has to work with C++98 and C++11 compilers. To learn and to enjoy ... from the given types or not. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - template argument type deduction from std::function return type with lambda

First of, I'm using C++11 (and my topic sucks). What I'm trying to do is write a generic template ... example to have it working with gcc? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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324 views

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c++ - Code Blocks, MinGW, Boost, and static linking issues

I am using Code Blocks with MinGW and am trying to get a simple program to compile with static linking. I ... (&myfunction); return 0; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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595 views

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c++ - Is std::vector thread-safe and concurrent by default? Why or why not?

What does it mean to make a dynamic array thread-safe and concurrent? Say, for example, std::vector. Two ... -safe and concurrent by default? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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297 views

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c++ - Undo a newline ( ) printed to command line

printf("Error %d ", 1); printf(" Status: %d%%", 50); prints Error 1 Status: 50% In this set up, is ... change text in a previous line? Thanks! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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326 views

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c++ - Can a compilation error be forced if a string argument is not a string literal?

Let's say I have these two overloads: void Log(const wchar_t* message) { // Do something } void Log(const ... one for extreme scenarios. :) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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296 views

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c++ - Force crash an application

I'm currently testing an application that my company wrote. One of the scenarios was to see what happens to the ... 't yield the same results. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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287 views

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c++ - Does std::array of std::array have contiguous memory?

Seems, that I found how to easily get normal 2D Array with contiguous memory in 2 lines of code: template<int N ... has changed in C++14? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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236 views

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c++ - placement new on a class with reference field

This is a code example from the C++20 spec ([basic.life]/8): struct C { int i; void f(); const C& ... ::launder, in the different C++ versions. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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259 views

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c++ - Declaring a string of fixed size

In C we do char buffer[100]; Is there a way to declare a fixed size std::string? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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488 views

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c++ - Custom memory alloc and dealloc which multiple Inheritance class

i want do memory management in my project. i do not want operator global new/delete so i implement a simple ... any way to solve this problem？ See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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324 views

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c++ - Determining struct member byte-offsets at compile-time?

I want to find the byte offset of a struct member at compile-time. For example: struct vertex_t { vec3_t position; ... is compile-time, my bad! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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248 views

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c++ - How to write the best possible is_callable trait for templated operator()

I have is_callable trait defined like this: #ifndef IS_CALLABLE_HPP #define IS_CALLABLE_HPP #include <type_traits> ... template arguments. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - automatic decay of lambda to function pointer when passing to template function

Is there a way to make a lambda decay to a pointer, without explicitly casting to the right signature? This would ... I'm back to square one. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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260 views

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c++ - How does shared_ptr work in if condition

In C++, I can write something like: shared_ptr<A> a_sp = someFunctionReturningSharedPtr(); if (a_sp) { cout < ... converts it to boolean value? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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274 views

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c++ - can we pass arrays as arguments to functions by this syntax, under upcoming c++0x standards?

suppose we have following function: void someFunction(int * araye){ for (int i=0;i<5;i++) cout <<araye[ ... approach to use that expression? . See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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194 views

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c++ - Why standard container iterators don't overload `->*`?

Apparently ->* doesn't work automagically if you overload ->, and has to be overloaded manually. Why iterators for ... line doesn't compile. } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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289 views

1 answer

c++ - Is it possible to move an item out of a std::set?

If I have an object that only allows move-only semantics - is it possible to move items from a set? I can't seem to find a way to do this. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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