Does C++ stl have a standard time class? Or do I have to convert to c-string before writing to a stream. Example, I want to output the current date/time to a string stream:
time_t tm(); ostringstream sout; sout << tm << ends;
In this case I get the current date/time written out as a number without any formatting. I can use
c- runtime function strftime to format tm first, but that seems like it should not be necessary if the stl has a time class that can be instantiated from time_t value
Not part of STL but well known library is boost.
I would go the way of using boost::date. Here are some examples: http://www.boost.org/doc/libs/1_40_0/doc/html/date_time/date_time_io.html#date_time.io_tutorial.
If you did not try out boost yet I encourage you to do so as it saves you from a lot of nasty issues, as it masks most OS dependent things like threading for example. Many things in boost are header only (template libraries). However datetime requires a lib or dll.
Nitpicking: The STL being the Standard Template Library deals with generic container and algorithms etc. and is unlikely to incorporate classes for date handling and calculation even in the future…
The C++ Standard Library itself includes the STL and a previous version of the C standard library. The latter offers some date and time related functions via #include <ctime> which has already been mentioned above.
If wrapping (or simply using) these functions is sufficient (and quicker) than pulling in boost, go with these. There is nothing wrong with them.
OK. Here is closest I have found about directly writing time to a stream:
time_t t(time(NULL)); // current time
tm tm(*localtime(&t));
std::locale loc(""); // current user locale
ostringstream sout;
const std::time_put<TCHAR> &tput =
std::use_facet<std::time_put<TCHAR> >(loc);
tput.put(sout.rdbuf(), sout, _T('\0'), &tm, _T('x'));
sout << ends;
CString sTest(sout.str().c_str());
A very helpful guide is the Apache C++ Standard Library Reference Guide http://stdcxx.apache.org/doc/stdlibref/time-put.html#sec13