Is it possible to safely use any of MapServer in a multi-threaded application?
Some of it, yes, with care. Or with Python 🙂 Programmers must either avoid using the unsafe components of MapServer or carefully place locks around them. Python’s global interpreter lock immunizes against MapServer threading problems; since no mapscript code ever releases the GIL all mapscript functions or methods are effectively atomic. Users of mapscript and Java, .NET, mod_perl, or mod_php do not have this extra layer of protection.