Recent questions tagged C++

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I just realised reading this page that the constructor of std::shared_ptr with a single pointer argument is ... the ownership Other thoughts ? 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 access static members of a class?

I am starting to learn C++ and Qt, but sometimes the simplest code that I paste from a book results in errors. ... 's wrong with the above 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++ - What's the difference between abs and fabs?

I checked the difference between abs and fabs on python here As I understand there are some difference regarding the ... types are: (int) 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 GoogleMock leaking my shared_ptr?

I use GoogleMock/GoogleTest for testing, and I'm seeing some strange behavior when a matcher has a shared_ptr to ... to use Mock::AllowLeak. 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++ - Explicit keyword on multi-arg constructor?

I recently came across some weird looking class that had three constructors: class Class { public: explicit Class(int ) ... , what does it mean? 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 std::unique_ptr operator* throw and operator-> does not throw?

In the C++ standard draft (N3485), it states the following: 20.7.1.2.4 unique_ptr observers [unique ... with the different ownership semantics? 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 you allocate an array with something equivalent to make_shared?

buffer = new char[64]; buffer = std::make_shared<char>(char[64]); ??? Can you allocate memory to ... make_shared is safer and more efficient. 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++ - binding of reference to a value of type drops qualifiers

I have the following source from the Text Accelerated C++. When I attempt to compile the source file I get ... Student_info); Now it compiles. 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++ - Getting around the reinterpret cast limitation with constexpr

In c++11, a constexpr expression cannot contain reinterpret casts. So for instance, if one wanted to ... getting around this limitation? 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++ - error C2220: warning treated as error - no 'object' file generated

I have below class class Cdata12Mnt { public: char IOBname[ID1_IOB_PIOTSUP-ID1_IOB_TOP][BOADNAM_MAX + 4]; char ExIOBname ... to fix this error? See Question&Answers more detail:os...

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

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347 views

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c++ - What happens to malloc'ed memory after exec() changes the program image?

I know that when I call one of the exec() system calls in Linux that it will replace the currently ... reclaimed by the operating system? 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 a sorted container in the STL?

Is there a sorted container in the STL? What I mean is following: I have an std::vector<Foo>, where Foo ... to call sort after every insertion. 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++ - Using default in a switch statement when switching over an enum

What is your procedure when switching over an enum where every enumeration is covered by a case? Ideally you'd like ... do it they way you do. 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 not always assign return values to const reference?

Let's say I have some function: Foo GetFoo(..) { ... } Assume that we neither know how this ... more verbose, are there any disadvantages? 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++ - Should I use long long or int64_t for portable code?

I have an open-source codebase that is written in both C and C++. I'm looking for an integer type that is ... go, given the above goal in mind. 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++ - ifstream: how to tell if specified file doesn't exist

I want to open a file for reading. However, in the context of this program, it's OK if the file doesn't ... fstream way to do this as well. 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 the number of elements in a initializer list cause an ambiguous call error?

Why are the first two calls to doSomething OK by the compiler, but using two elements in the list causes an ... : ambiguous call 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++ - What is the actual use of "signed" keyword?

I know that unsigned integers are only positive numbers (and 0), and can have double the value compared to a ... you use the signed keyword? See Question&Answers more detail:os...

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

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397 views

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c++ - Why do round() and ceil() not return an integer?

Once in a while, I find myself rounding some numbers, and I always have to cast the result to an integer ... love to have some explanations! 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++ - Does overloading '==' get you '!='?

If I manually overload the == operator for a structure, do I get the != operator for free (presumably defined ... good answers have been given. 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++ - ipch files on a Visual Studio project

I am finding an ipch folder in my project whose files are having an ipch extension. Plus, they are quite voluminous. Can I get rid of them? 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 safe to rename argc and argv in main function?

A lot of programs use standard names for a number of arguments and arrays of strings. The prototype of main ... for some kind of 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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239 views

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c++ - Importing .dll into Qt

I want to bring a .dll dependency into my Qt project. So I added this to my .pro file: win32 { ... pz assembly architechture, definitely a n00b. 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++ - Solving a linear system with Lapack's dgeqrf_

I am trying to factorize a matrix with the QR factorization in C++, using Lapack's functions in ... corresponding system of linear equations? 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++ - windows 10 screen coordinates are offset by 7

I'm coding in c++ on windows 10 - straight win32 API. I wanted to make a window show up in the top right of the ... r->left, r->bottom-r->top); 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++ - Getting a dump of a process that crashes on startup

On a customer machine (WinXP SP2) to which I have no access, I have a Win32 EXE (unmanaged C++) that ... that crashes on startup on Win32? 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++ - mmap for writing sequential log file for speed?

I want to write log file, unstructured format (one line at a time), using mmap (for speed). What ... /pointers to best practices appreciated. 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++ - External calls are not supported - CUDA

Objective is to call a device function available in another file, when i compile the global kernel it shows the following ... -o test.o -I"." See Question&Answers more detail:os...

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

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