Recent questions tagged C++

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I've tried to compile simple hello world on Fedora 20 with Clang, and I get the following output: d.cpp:1:10 ... any idea how to resolve it. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How to read the screen pixels?

I want to read a rectangular area, or whole screen pixels. As if screenshot button was pressed. How i ... ); DeleteObject(hCaptureBitmap); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - On how to recognize Rvalue or Lvalue reference and if-it-has-a-name rule

I was reading Thomas Becker's article on rvalue reference and their use. In there he defines what he ... rvalueness/lvaluness of an expression? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Special simple random number generator

How to create a function, which on every call generates a random integer number? This number must be most ... or similar stuff is allowed. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Serializing OpenCV Mat_<Vec3f>

I'm working on a robotics research project where I need to serialize 2D matrices of 3D points: basically each pixel ... ways to do it? Thanks! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How can I use non-default delimiters when reading a text file with std::fstream?

In my C++ code, I want to read from a text file (*.txt) and tokenize every entry. More specifically, I ... space as delimiters at the same time. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - How do you throttle the bandwidth of a socket connection in C?

I'm writing a client-server app using BSD sockets. It needs to run in the background, continuously ... to achieve this, programmatically? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - std::unique_ptr, deleters and the Win32 API

In VC2012, I want to create a mutex in a constructor using a unique pointer and a deleter, so that I don't ... magic I need to know about? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - In Visual Studio, `thread_local` variables' destructor not called when used with std::async, is this a bug?

The following code #include <iostream> #include <future> #include <thread> #include <mutex> std::mutex m; struct ... will always be printed. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - linking with clang++ on OS X generates lots of symbol not found errors

I'm trying to compile some C++ code (including C++11 features) on OS X 10.8 using the clang++ compiler. I ... make: *** [Analysis.so] Error 1 See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why was 1 << 31 changed to be implementation-defined in C++14?

In all versions of C and C++ prior to 2014, writing 1 << (CHAR_BIT * sizeof(int) - 1) caused undefined ... was this change made in C++14? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why is my object not being copied when move constructor is deleted?

I'm trying to use this code to demonstrate the use of the copy-constructor. My presumption was that when I have ... :5:5: error: declared here See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - xcode with boost : linker(Id) Warning about visibility settings

I have been using a boost framework from the link below for my iPhone Xcode project: https://goodliffe.blogspot. ... So my solution did work! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - When is a function try block useful?

I'm wondering when programmers use function try blocks. When is it useful? void f(int i) try { if ( i < 0 ) ... .fct.def] in the C++ Standard. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - One or more multiply defined symbols found

DebugUtil.h #ifndef DEBUG_UTIL_H #define DEBUG_UTIL_H #include <windows.h> int DebugMessage(const char* message) { ... shouldn't happen See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - error: member access into incomplete type : forward declaration of

I have two classes in the same .cpp file: // forward class B; class A?{ void doSomething(B * b) { b-> ... idea of how to resolve my problem ? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Refreshing the auto complete (IntelliSense) database in Visual Studio

I've noticed that the auto complete feature in Visual Studio no longer works properly once my project has reached ... Studio 2010 as well. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Why is there no support for concatenating std::string and std::string_view?

Since C++17, we have std::string_view, a light-weight view into a contiguous sequence of characters that ... ::string_view in the standard? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Converting YUV into BGR or RGB in OpenCV

I have a TV capture card that has a feed coming in as a YUV format. I've seen other posts here similar to this question ... 1 - 0.114)/0.436); } See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Serialization of struct

Suppose i have a struct whose member values i want to send over the network to another system using winsock 2. ... posts did not help much. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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184 views

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c++ - Conflict between dynamic linking priority in OSX?

There is a dynamic-linking-conflict between different libjpeg dynamic libraries on OSX. First there is a standard ... rank higher priority-wise? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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232 views

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c++ - Literal initialization for const references

How does the following code work in C++? Is it logical? const int &ref = 9; const int &another_ref = ref ... studying Lippman's C++ Primer. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Compile-time or runtime detection within a constexpr function

I was excited when constexpr was introduced in C++11, but I unfortunately made optimistic assumptions about ... would be compromised. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Throwing an exception from within a signal handler

We have a library that deals with many aspects of error reporting. I have been tasked to port this library to ... , is not a viable option. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Constructor initialization Vs assignment

Let us consider the following classes class test1 { private: int a; int b; public: test1():a(0),b(0){} ... not, then how are these initialized? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Is there a way to automatically avoiding stepping into certain functions in Visual Studio?

I'm aware of the "Enable just my code" debug option, but that only works for managed code. I'm looking ... one of the function's parameters. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - Should I use shared_ptr or unique_ptr

I've been making some objects using the pimpl idiom, but I'm not sure whether to use std::shared_ptr or std:: ... or bad thing. Is this correct? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - I cannot pass lambda as std::function

Let's focus on this example: template<typename T> class C{ public: void func(std::vector<T>& vec, std::function< ... it with std::bind as well. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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