IMP is designed to run on a wide variety of platforms. To detect problems on other platforms we provide nightly test runs on the supported platforms for code that is part of the IMP repository.

In order to make it more likely that your code works on all the supported platforms:

• avoid the use of and and or in C++ code; use && and || instead.
• avoid friend declarations involving templates; use the preprocessor, conditionally on the symbols SWIG and IMP_DOXYGEN to hide code as needed instead.
• don't use Python modules or functions that aren't available in Python 2.7 (the oldest version of Python supported by IMP). For example, don't use f strings.
• try to write Python code that also works in Python 3 (IMP supports both Python 2 and Python 3 in one codebase). Most obviously, in Python 3, print is a function, not a statement. So write print("foo") rather than print "foo" - the former works in Python 2 too. To catch a lot of Python 3-incompatible code quickly, add from __future__ import print_function, division, absolute_import at the very top of your Python submodules (top-level modules have this already).
• if you must use an external C++ library, it needs to have a very permissive open source license (such as BSD or LGPL - not GPL) and note that this will reduce the number of potential users of your code (since it's another dependency to find).
• try to avoid Linux- or Mac-centric coding that won't work on Windows. For example, use os.path.join to join paths in Python, rather than adding the '/' character. Write utility scripts in Python (which is available on Windows, since the rest of IMP requires it) not as shell scripts, Perl scripts, etc.