stdstring

I am coming up against a vexing conundrum in my code base. I can't quite tell why my code generates this error, but (for example) std::string does not. class String { public: String(const char*str); friend String operator+ ( const String& lval, const char *rval ); friend String operator+ ( const char *lval, const String& rval ); String operator+ ( const String& rval ); }; The implementation of these is easy enough to imagine on your own. My driver program contains the following: String result, lval("left side "), rval("of string"); char lv[] = "right side ", rv[] = "of string"; result = lv +

When I create a std::string using the default constructor, is ANY memory allocated on the heap? I'm hoping the answer does not depend on the implementation and is standardized. Consider the following: std::string myString; Unfortunately, the answer is no according to N3290. Table 63 Page 643 says: data() a non-null pointer that is copyable and can have 0 added to it size() 0 capacity() an unspecified value The table is identical for C++03. It is implementation dependent. Some string implementations use a small amount of automatically allocated storage for small strings, and then dynamically

I'm trying to put std::string s into boost::lockfree::queue s so that my threads can update each other with new data. When I try to use boost::lockfree::queue<std::string> updated_data; , g++ says : In instantiation of 'class boost::lockfree::queue >': error: static assertion failed: (boost::has_trivial_destructor::value) error: static assertion failed: (boost::has_trivial_assign::value) I've been shown generally what these errors mean , but I have no hope of ever fixing this myself, as I'm almost brand new to c++. Is there an alternative way to pass text data between threads with lockfree ?

I found this really nice piece of code that converts a string to a System:String^ as in: System::String^ rtn = gcnew String(move.c_str()); // 'move' here is the string I'm passing rtn back to a C# program. Anyways, inside the function where this code exists, I'm passing in a System::String^ . I also found some code to convert a System:String^ to a string using the following code: pin_ptr<const wchar_t> wch = PtrToStringChars(cmd); // 'cmd' here is the System:String size_t convertedChars = 0; size_t sizeInBytes = ((cmd->Length + 1) * 2); errno_t err = 0; char *ch = (char *)malloc(sizeInBytes);

I tried two different ways to append an int to a std::string , and to my surprise, I got different results: #include <string> int main() { std::string s; s += 2; // compiles correctly s = s + 2; // compiler error return 0; } Why does it compile and work correctly when I use the += operator, but fail when I use the + operator? I don't think the question is like How to concatenate a std::string and an int? In that question,no answer uses += operator.And the difference between += and + operator of std::string is the key to solve my doubt. Frankly,the question is a good example for explaining why

Is it valid to create an iterator to end(str)+1 for std::string ? And if it isn't, why isn't it? This question is restricted to C++11 and later, because while pre-C++11 the data was already stored in a continuous block in any but rare POC toy-implementations, the data didn't have to be stored that way. And I think that might make all the difference. The significant difference between std::string and any other standard container I speculate on is that it always contains one element more than its size , the zero-terminator, to fulfill the requirements of .c_str() . 21.4.7.1 basic_string

In response to discussion in Cross-platform strings (and Unicode) in C++ How to deal with Unicode strings in C/C++ in a cross-platform friendly way? I'm trying to assign a UTF-8 string to a std::string variable in Visual Studio 2010 environment std::string msg = "महसुस"; However, when I view the string view debugger, I only see "?????" I have the file saved as Unicode (UTF-8 with Signature) and i'm using character set "use unicode character set" "महसुस" is a nepali language and it contains 5 characters and will occupy 15 bytes. But visual studio debugger shows msg size as 5 My question is: How

I am moving my project from Visual Studio 06 to 2010. While doing so, I have observed this behavior in my code. I have a Get string function that look like this: string GetTheStr() { return strSomeStdString; } Then there is another function that call above get function like this: const char* ptrStr = (char *)GetTheStr().c_str(); the value of string pointed by ptrStr is "" above code was working fine in visual studio 06 but not on visual studio 2010. Then I tried few experiments: std::string str = GetTheStr(); // -> value inside str displayed correctly const char* PtrCStr = str.c_str(); // ->