Recent questions tagged C++

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c++ - Why is std::queue not thread-safe?

The topic says it. I don't understand why the std::queue (or in general: any queue) is not thread-safe ... as there is no signaling involved. 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 do I convert a big-endian struct to a little endian-struct?

I have a binary file that was created on a unix machine. It's just a bunch of records written one after ... couple bytes would be great, too! 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++ - Combing an External Event Loop with Qt's

I'm building a Qt client for the open-source client/server 4X strategy game Thousand Parsec. This a Google ... t really understand it. 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++ - why is the destructor call after the std::move necessary?

In The C++ programming language Edition 4 there is an example of a vector implementation, see relevant code at the ... / destroy } return oo; } 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++11 Thread waiting behaviour: std::this_thread::yield() vs. std::this_thread::sleep_for( std::chrono::milliseconds(1) )

I was told when writing Microsoft specific C++ code that writing Sleep(1) is much better than Sleep(0) for spinlocking ... } // Do something! } 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++ - Type trait to check that all types in a parameter pack are copy constructible

I need a type trait to check whether all types in a parameter pack are copy constructible. This is what I've ... , how to solve the 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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c++ - Initializing Constant Static Array In Header File

I have just found out that the following is not valid. //Header File class test { const static char array[ ... best place to initialize 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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c++ - Lvalue to rvalue reference binding

The compiler keeps complaining I'm trying to bind an lvalue to an rvalue reference, but I cannot see how. ... being reinterpreted as an lvalue? 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++ - Extend the life of threads with synchronization (C++11)

I have a program with a function which takes a pointer as arg, and a main. The main is creating n threads, each ... mix_data(myp); } 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++ - Qt, MSVC, and /Zc:wchar_t- == I want to blow up the world

So Qt is compiled with /Zc:wchar_t- on windows. What this means is that instead of wchar_t being a typedef ... developers deal with this mess? 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++ - Are free operator->* overloads evil?

I was perusing section 13.5 after refuting the notion that built-in operators do not participate in overload ... real-world use cases? 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 fstream to read every character including spaces and newline

I wanted to use fstream to read a txt file. I am using inFile >> characterToConvert, but the problem is ... way to go about accomplishing 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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c++ - 'uint32_t' identifier not found error

I'm porting code from Linux C to Visual C++ for windows. Visual C++ doesn't know #include <stdint.h> so ... found errors. How can it be solved? 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 argc not a constant?

int main( const int argc , const char[] const argv) As Effective C++ Item#3 states "Use const whenever ... argc is modified in a program? 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 makes this usage of pointers unpredictable?

I'm currently learning pointers and my professor provided this piece of code as an example: //We cannot predict ... see nothing wrong with 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 pretty-print STL containers in GDB?

I've followed the instructions on the GDB wiki to install the python pretty-printers for viewing STL containers. My ~/ ... comes with GDB 7.4. 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 a buffer of bytes be signed or unsigned char buffer?

Should a buffer of bytes be signed char or unsigned char or simply a char buffer? Any differences between C and C++? 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++ - why do I need std::condition_variable?

I found that std::condition_variable is very difficult to use due to spurious wakeups. So sometimes I need to set ... I prefer choose it myself. 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 should I use asserts?

I never got the idea of asserts -- why should you ever use them? I mean, let's say I were a formula driver ... the way, I'm using unit tests. 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::stack use std::deque by default?

Since the only operations required for a container to be used in a stack are: back() push_back() ... is still amortized constant anyways. 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 this pointer causes strange deoptimization in hot loop

I recently came across a strange deoptimization (or rather missed optimization opportunity). Consider this ... manual optimization technique. 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++ - Get a pointer to STL container an iterator is referencing?

For example, the following is possible: std::set<int> s; std::set<int>::iterator it = s.begin(); I wonder if ... *(); // something like 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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c++ - How to pass multi-argument templates to macros?

Say I have a macro like this: #define SET_TYPE_NAME(TYPE, NAME) template<typename T> std::string name(); ... there any way around 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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c++ - Shift operands sequenced in C++17

I read in the C++17 Standard $8.5.7.4: The expression E1 is sequenced before the expression E2. for shift ... ++) also gives a wrong result. 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++ - Sequencing of function parameter destruction

According to C++14 [expr.call]/4: The lifetime of a parameter ends when the function in which it is ... not use the standard sequencing terms? 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++ - Calling virtual function of derived class from base class constructor?

I′m trying to accomplish the same which is described in a previous question: virtual function call from base ... -inheritance.html#faq-23.6 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++ - Multidimensional array indexing using pointer to elements

As far as I know, multidimensional array on stack will occupy continuous memory in row order. Is it undefined ... + Standard would be best. 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 do template classes allow member functions which cannot compile?

class P { }; template< typename P > class C : public P { public: void f() { P::f(); } }; int ... is ill-formed in the non-template scenario. See Question&Answers more detail:os...

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

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