[gmpi] Re: Linux C++ question

Jeff McClintock wrote:

i wasn't trying to show the whole thing. but your reply makes the
point i was trying to make anyway :) yes, a singleton needs to cleanup
at exit. what is "at exit"? we want it to be DLL-unload time, but can
the language ensure that this happens with a static object? the C++
working group discussion suggests that it can. however, angus has
described how OS X still has a problem in fulfilling this.


I understand GNU fixed this bug 3 years ago. If OSX doesn't support fundamental keywords like 'static' I'll eat my cat. 

OS X supports the "static" keyword, yes.

The problem is that a static object has to be constructed and destroyed... atexit is part of the invisible machinery that does this (there are equivalent routines on Windows). This works correctly in OS X GCC applications, correctly in OS X dylibs for file-scope / global-scope statics, but is broken for OS X GCC dylibs for function-scope statics.

The constructors get called at the right time - at module-load. That's all well and good. The problem is, the destructors get called at application-exit, NOT at module-unload. If the module was already unloaded -- kaboom, your application crashes on quit, as atexit calls off in to space.

Bearing in mind that OS X is a big part of the commercial plug-in market, and that XCode (Apple's visual IDE for GCC) is probably the most popular compiler on OS X now, it's important to support it.



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