int to std::string?

Question

I have following code:

Tools::Logger.Log(string(GetLastError()), Error);

GetLastError() returns a DWORD a numeric value, but the constructor of std::string doesnt accept a DWORD.

What can I do?

thanks in advance

Answer 1

Use Boost's lexical_cast for simple cases such as the above:

Tools::Logger.Log(lexical_cast<string>(GetLastError()), Error);

Answer 2

You want to convert the number to a string

std::ostringstream os;
os << GetLastError();
Log(os.str(), Error);

Or boost::lexical_cast:

Log(boost::lexical_cast<std::string>(GetLastError()), Error);

Cheers

Answer 3

what i normally do is:

std::ostringstream oss;
oss << GetLastError() << " :: " << Error << std::endl;
Tools::Logger.Log(oss.str()); // or whatever interface is for logging

Answer 4

You want to read up on ostringstream:

int main()
{
   std::ostringstream stream;
   int i = 5;
   stream << i;
   std::string str = stream.str();
}

Answer 5

Use std::stringstream.

std::stringstream errorStream;
errorStream << GetLastError();
Tools::Logger.Log(errorStream.str(), Error);

Answer 6

As all guys here suggested, implementation will use stringstream.
In my current project we created function

template <typename T>
std::string util::str::build( const T& value );

to create string from any source.

So in our project it would be

Tools::Logger.Log( util::str::build(GetLastError()) );

Such usage of streams in the suggested way wouldn't pass my review unless someone wrap it.

Answer 7

I've linked this article before, by maybe one more time wouldn't hurt. Read The String Formatters of Manor Farm by Herb Sutter. It's a great comparison of the different ways to convert data to strings, including std::stringstream, Boost::lexical_cast, sprintf, snprintf, and std::strstream.

Answer 8

You can use STLSoft's winstl::int_to_string(), as follows:

Tools::Logger.Log(winstl::int_to_string(GetLastError()), Error);

Also, if you want to lookup the string form of the error code, you can use STLSoft's winstl::error_desc.

There were a bunch of articles in Dr Dobb's about this a few years ago: parts one, two, three, four. Goes into the subject in great detail, particularly about performance.