cant include sstream g++ query

hi
I am relatively new to C++ and want to use the sstream class however my compiler at work is GNU's g++ which only has the old strstream.h package. I found sstream code at the following link as par t of the GNU IO library.
URL
i copied it to a file i created called stream.h in my working directory and included that in my program. It seems to give me the functionality I require. (have not done substatntial coding with it yet as I want to find out if this is a legitimate way of using the class. ) Are there any sideeffects with doing this rather than geting it as part of the standard library? I don't want to mess about with updateing the companies library. should I just try to use the standard string, and strtream.h classes?
thanking you p