I've been out of the C++ game for about 10 years and I want to get back in and start on a commercial app. What libraries are in use these days?
I looking to be cross-platform compatible (as much as possible out-of-the-box).
What libraries to do you rely on? What features do they provide that make them "indispensable"?
See my answer below for a summary.
Qt is a great addition with the new LGPL licensing model which allows it to be used in commercial software free of charge.
It's the perfect place to start with a new cross platform project.
Boost is a huge one (well, technically a bunch of big ones).
Qt is quite simply excellent. Its cross platform, and has modules for pretty much all the things you would want to do in an application: networking, database, ui, xml and a bunch of other stuff.
Adaptive Communication Environment (ACE) is a cross-platform OO network programming toolkit written in C++. Wikipedia has a good description.
http://loki-lib.sourceforge.net/ might also be good addition.
It's another template library, which introduces typelists, and implementations for various design patterns.
I never used it, but I read Alexandrescu's book to get a better understanding of templates.
familiarity with stl and boost are essential to any serious c++ developer. I've heard good things about Qt, but didn't know it was free for commercial use until the post above. Thanks Brian R. Bondy.
Google Mock and Google Test for Mock Objects in C++ and Unit Testing.
Sorry for repeating some of the stuff already written, but:
(Should at least get you started)
The STL (Standard Template Library) should be provided by all decent C++ compilers. If you don't know it, you should. If you think you don't need it, it's fine if you have good reasons, but you have to know it first anyway.
Boost ( http://www.boost.org ) is a big set of libraries that is complementary to the STL. Most of the STL additions are first provided in Boost before getting to the official standard library status. Most of the time, you find in Boost what you need when it's related to general algorithms/structures. The main exception is GUI lib.
A tiny alternative to Boost is POCO ( http://pocoproject.org/ ). It provides some of the most essential libraries that are already in Boost, but implemented in another way, easier to read an learn if you're not yet a C++ specialist. It's not as "complete" (or "with as much variety" should I say) than Boost, but it's sometime interesting. Learn a bit about it to know your choices.
For GUI, as other suggested, in C++, QT might be the more useful GUI (and other tools) library at the moment. Alternatives are wxWidgets and GTK (gtkmm) for the more known.
All those libraries are cross-platform.
Cross-platform libraries that are free for commercial (or non-commercial) applications
Feel free to expand this list
CGAL is an excellent c++ library for computational geometry
www.cgal.org
My toolset:
I agree with the general consensus that boost, STL and QT are probably at the top of the general list.
I often need a decent cross platform http library and I've always had good luck with libCurl. I believe QT has some of this functionality as well, but if QT doesn't cut it for some reason, definitely have a look at libCurl.
In regards to "Cross-platform libraries that are free for commercial (or non-commercial) applications", POCO should be added to Networking, Threading and Logging categories.
Besides all the great libraries already listed, I find the combination of xerces for XML (including XSD validation) and xalan for XSLT to be useful (xalan is built on top of xerces). AFAIK neither QT or POCO have XSLT functionality (unless it's been added since I last used them).