Recent questions tagged C++

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c++ - Weird GCC array initialization behavior

I encountered a variant of this code when looking at another question (the original code used a std::thread instead of ... or just a plain bug? 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++ - What is the "interface" keyword in MSVC?

I'm looking through the Windows 8.1 SDK and in UnknownBase.h I'm seeing things like typedef interface IUnknown ... anyone clue me in here? 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 it allowed to call destructor explicitly followed by placement new on a variable with fixed lifetime?

I know that calling destructor explicitly can lead to undefined behavior because of double destructor calling, like ... have any const members. 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++ - Declaration of method changes meaning of symbol

For the following code: struct foo {}; struct A { typedef foo foo_type; void foo(); }; GCC gives a compiler ... gcc and clang accept the code. 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++ - Behaviour of std::list:begin() when list is empty

Does the following give defined results in terms of the C++ standard? std::list<int> myList; std::list<int> ... d like a more definitive answer. 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 is a vector of pointers not castable to a const vector of const pointers?

The type vector<char *> is not convertible to const vector<const char*>. For example, the following gives a compilation ... by the C++ FQA here. 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++ - Modifying a data structure while iterating over it

What happens when you add elements to a data structure such as a vector while iterating over it. Can I not do this? I tried ... j << " .. "; } } 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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792 views

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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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519 views

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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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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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380 views

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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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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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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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308 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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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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415 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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602 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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244 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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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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333 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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398 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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260 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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416 views

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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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