Recent questions tagged C++

0 votes

480 views

1 answer

Is there a cross-platform function in Qt that is equivalent to the MoveFile function in Windows and the mv command in Linux? See Question&Answers more detail:os...

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

0 votes

289 views

1 answer

c++ - QT Repaint/Redraw/Update/Do Something

I'm New to QT. I understand that you can force a display refresh, but I've pulled all my hair out trying ... help, advice, and or sample code. See Question&Answers more detail:os...

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

0 votes

238 views

1 answer

c++ - How do I prevent my 'unused' global variables being compiled out?

I'm using static initialisation to ease the process of registering some classes with a factory in C++. ... unit was entirely ignored. See Question&Answers more detail:os...

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

0 votes

392 views

1 answer

c++ - Vector of vectors, reserve

Suppose I want to represent a two-dimensional matrix of int as a vector of vectors: std::vector<std::vector< ... inner vector's size changes? See Question&Answers more detail:os...

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

0 votes

529 views

1 answer

c++ - Why do ZeroMemory, etc. exist when there are memset, etc. already?

Why does ZeroMemory(), and similar calls exist in the Windows API when there are memset and related calls in the C ... is "depends". On what? See Question&Answers more detail:os...

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

0 votes

646 views

1 answer

c++ - constexpr error at compile-time, but no overhead at run-time

There is a well-known trick to cause a compile-time error in the evaluation of a constexpr function by doing ... (C++14) change anything? See Question&Answers more detail:os...

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

0 votes

390 views

1 answer

c++ - Assignment operator not available in derived class

The assignment operator in base class does not seem to be available in derived class. Given this code: #include < ... 'int') What is happening? See Question&Answers more detail:os...

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

0 votes

451 views

1 answer

c++ - How to call a constructor on an already allocated memory?

How can I call a constructor on a memory region that is already allocated? See Question&Answers more detail:os...

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

0 votes

296 views

1 answer

c++ - Destructors and noexcept

I am a little bit confused with destructors and noexcept. My understanding was that in C++11 any destructor ... with user-defined destructors? See Question&Answers more detail:os...

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

0 votes

221 views

1 answer

c++ - How to determine which compiler has been used to compile an executable?

From a compiled file, can I see which compiler has been used to generate the file? See Question&Answers more detail:os...

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

0 votes

497 views

1 answer

c++ - How can I intentionally discard a [[nodiscard]] return value?

Say I have [[nodiscard]] int foo () { return 0; } int main () { foo (); } then error: ignoring return ... to discard this [[nodiscard]] value"? See Question&Answers more detail:os...

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

0 votes

673 views

1 answer

c++ - Using std::make_unique with a custom deleter

In using std::unique_ptr with a custom deleter I desire to use std::make_unique rather than a raw new. I am ... be to use std::unique_ptr. See Question&Answers more detail:os...

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

0 votes

179 views

1 answer

c++ - Visual Studio can't 'see' my included header files

I created an empty 'Demo' project in Visual Studio 2008 and added some existing projects to my solution. Included ... can be fixed? Thanks. See Question&Answers more detail:os...

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

0 votes

276 views

1 answer

c++ - Is the specification of `bsearch` in C++11 & C++14 defective?

Following on from my answer to this question, in both C++11 and C++14: [C++11, C++14: 25.5/2]: The ... translation units. [..] Is this a defect? See Question&Answers more detail:os...

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

0 votes

196 views

1 answer

c++ - Is capacity copied in a vector?

Take the following code: std::vector<int> a; a.reserve(65536); std::vector<int> b(a); //NOTE: b is ... say anything about this or is it silent? See Question&Answers more detail:os...

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

0 votes

242 views

1 answer

c++ - Why is there no std::stou?

C++11 added some new string conversion functions: http://en.cppreference.com/w/cpp/string/basic_string/stoul It ... functions in C++11? See Question&Answers more detail:os...

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

0 votes

111 views

1 answer

c++ - Trying to understand [basic.def.odr]/2 in C++14 (N4140)

The Example in [basic.def.odr]/2 starts with the following sentence: In the following example, the set of ... // a definition is required See Question&Answers more detail:os...

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

0 votes

180 views

1 answer

c++ - signal handling

I'm just playing with signal in Mac OS X. Why does the following code not produce the default behavior of ... and I have to interrupt it. See Question&Answers more detail:os...

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

0 votes

545 views

1 answer

c++ - Play a Live video Stream using Qt

Given below is the code for playing a video file using Qt. Instead of playing the video I want to play a live video ... (); return a.exec(); } See Question&Answers more detail:os...

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

0 votes

253 views

1 answer

c++ - Compiling and running GTK+ application on Windows 7

System: Windows7, 32 bit, GTK 2.24.10, mingw I am trying to write basic helloworld.c type GTK based ... and compiling using gcc under windows? See Question&Answers more detail:os...

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

0 votes

458 views

1 answer

c++ - ZMQ DEALER - ROUTER Communication

I am currently working on a project that requires some communication over the network of a different data types from ... I haven't clear this See Question&Answers more detail:os...

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

0 votes

153 views

1 answer

c++ - single expression helper for compile-time enforced constexpr function evaluation possible?

@cyberpunk_ is trying to achieve something and made some questions about it but all the chase boils down to this: ... to do should not matter. See Question&Answers more detail:os...

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

0 votes

199 views

1 answer

c++ - How do I loop over consecutive pairs in an STL container using range-based loop syntax?

How do I create a custom class to loop over consecutive pairs of items in a STL container using a range- ... copy objects in the container. See Question&Answers more detail:os...

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

0 votes

289 views

1 answer

c++ - std::map - how to change key sorting?

I have a problem with std::map. I'm using it to map some list of pairs under a specific index: map<string, ... 's some other way to solve it? See Question&Answers more detail:os...

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

0 votes

593 views

1 answer

c++ - OpenCV rgb value for cv::Point in cv::Mat

I've looked at different questions already here on StackOverflow, but none seems to helps. What I want to do ... gives the right value!! See Question&Answers more detail:os...

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

0 votes

126 views

1 answer

c++ - How to create new Type in MPI

I am new to MPI and I want to create a new datatype for Residence struct. I just want to see if ... ,&new_type); MPI_Type_commit(&new_type); } See Question&Answers more detail:os...

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

0 votes

595 views

1 answer

c++ - asio::async_write and strand

asio::async_write(m_socket, asio::buffer(buf, bytes), custom_alloc(m_strand.wrap(custom_alloc(_OnSend)))); Does this ... s just for my_handler?) See Question&Answers more detail:os...

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

0 votes

137 views

1 answer

c++ - How to understand function recursion precisely?

I am currently programming some divide-conquer algorithms, where function recursions are used everywhere, but I have ... Thanks for your help! See Question&Answers more detail:os...

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

Categories

Just Browsing Browsing

Most popular tags