如果使用std::string本身的成员函数或者操作符来操作std::string,它本身就是深拷贝的; 如果使用指针直接操作std::string源数据,会绕过“写时复制”机制,需要主动deep copy,以避免数据误写。
Deep copy std::string::c_str() to char * 本问题已经有最佳答案,请猛点这里访问。目前我有一个复杂的功能,我和我们的团队不想重构利用STD::字符串,它...
// deep copy to avoid misuse static void TestStringCopyCase4() { std::string a = "Hello World";std::string b = a.c_str(); // deep copy char* char_array = (char *)b.c_str();char_array[0] = 'h';printf("pointer of a: %p\n", a.c_str());printf("pointer of b: %p\...
c++gcccopy-constructordeep-copystdstring 13 我想知道自己是否理解错了什么:从std::string创建的复制构造函数不会复制其内容吗? string str1 = "Hello World"; string str2(str1); if(str1.c_str() == str2.c_str()) // Same pointers! printf ("You will get into the IPC hell very soon!!"...
2019-12-24 17:52 − 首先先看一段代码 import copy a = [1, 2, 3, [4]] b = a c = a.copy() d = copy.deepcopy(a) e = copy.copy(a) a.append(4) a[3].append(5) print('a值为 {} 地址为 {}'.fo... 鹄望 0 568 std::shared_mutex和std::mutex的性能对比(banchmark...
One major missed optimization is that you only ever make deep copies of the string data. If passed an temporary xvalue, a TString&&, you would be able to re-use the container. For example, upper and lower could iterate through and replace each character of the existing string, reverse co...
class DeepString { DeepString(const DeepString& other); DeepString& operator=(const DeepString& other); char* internal_; public: explicit DeepString( const string& toCopy): internal_(new char[toCopy.size()+1]) { strcpy(internal_,toCopy.c_str()); } ~DeepString() { delete[] int...
class DeepString { DeepString(const DeepString& other); DeepString& operator=(const DeepString& other); char* internal_; public: explicit DeepString( const string& toCopy): internal_(new char[toCopy.size()+1]) { strcpy(internal_,toCopy.c_str()); } ~DeepString() { delete[] internal...
Long story short, you need to deep-copy the string. Why do you want a char* to point to a std::string buffer anyway? There are circumstances when you need to deep copy a string and there are circumstances when you don't need to deep copy a string. It depends on concrete context....
Obviously returning string views, creating string views, using substr is definitely much faster than deep copies of std::string . However, the initial performance tests showed that std::string is usually highly optimized and sometimes string_view doesn’t win that much. The C++17 Series This ...