stringstream

Consider this program: #include <iostream> #include <string> #include <sstream> #include <cassert> int main() { std::istringstream stream( "-1" ); unsigned short n = 0; stream >> n; assert( stream.fail() && n == 0 ); std::cout << "can't convert -1 to unsigned short" << std::endl; return 0; } I tried this on gcc (version 4.0.1 Apple Inc. build 5490) on OS X 10.5.6 and the assertion is true; it fails to convert -1 to an unsigned short. In Visual Studio 2005 (and 2008) however, the assertion fails and the resulting value of n is the same as what you would expect from an compiler generated

Presently, I set the value of a std::vector<char> from an std::ostringstream as follows: void foo(std::vector<char> &data, std::stringstream &stream) { data = std::vector<char>(stream.str().begin(), stream.str().end()); } I'm wondering if there is a more efficient way to do this with STL in C++ or whether the method I give here is considered appropriate? Would I be better off using std::stringstream instead? Your method invokes undefined behaviour . stream.str() returns a string by-value , aka a temporary string. You take the begin iterator of one temporary and the end iterator of the other,

The following test program returns different results depending on whether I'm using libc++ or libstdc++. #include <sstream> #include <iostream> int main() { int a = 0; void* optr = &a; void* iptr; std::stringstream ss; ss << optr; std::cout << ss.str() << '\n'; ss >> iptr; std::cout << iptr << '\n'; return 0; } I'm using the following version of clang from Xcode 5 on OSX 10.9.2 $ xcrun clang++ --version Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn) Target: x86_64-apple-darwin13.1.0 Thread model: posix Here's the output of the test when built with libstdc++ and libc++ $ xcrun

These threads do NOT answer me: resetting a stringstream How do you clear a stringstream variable? std::ifstream file( szFIleName_p ); if( !file ) return false; // create a string stream for parsing std::stringstream szBuffer; std::string szLine; // current line std::string szKeyWord; // first word on the line identifying what data it contains while( !file.eof()){ // read line by line std::getline(file, szLine); // ignore empty lines if(szLine == "") continue; szBuffer.str(""); szBuffer.str(szLine); szBuffer>>szKeyWord; szKeyword will always contain the first word, szBuffer is not being reset,

How can I make this simple class movable? What I thought was correct just produces a wall of errors... #include <iostream> #include <sstream> #include <utility> class message { public: message() = default; // Move constructor message( message &&other ) : stream_( std::move( other.stream_ ) ) // Nope {} // Move assignment message &operator=( message &&other ) { if ( this != &other ) { stream_ = std::move( other.stream_ ); // Nope #2 } return *this; } private: message( const message & ) = delete; message &operator=( const message & ) = delete; std::stringstream stream_; // Other member variables

I'm asking in context of performance. Is stringstream simply a string/vector, so writing to it may result in its whole content being copied to a bigger chunk of memory, or is it done in a more tricky way (say, a list of strings or whatever)? It's up to the standard library vendor how to implement stringstream (or any library feature for that matter). You can look at the sstream header shipped with your compiler to see how it's implemented there. That much on the theoretical side... As far as practical experience and measurements show, ostringstream is often slow compared to other methods for

How to force std::stringstream operator >> to read an entire string instead of stopping at the first whitespace? I've got a template class that stores a value read from a text file: template <typename T> class ValueContainer { protected: T m_value; public: /* ... */ virtual void fromString(std::string & str) { std::stringstream ss; ss << str; ss >> m_value; } /* ... */ }; I've tried setting/unsetting stream flags but it didn't help. Clarification The class is a container template with automatic conversion to/from type T. Strings are only one instance of the template, it must also support other