From: "Robert Ramey" <ramey@rrsd.com>
Vladimir Prus wrote:
In this case:
void f(){ static X x; ... }
The constructor for x is invoked the first time f() is called. In this
Yes.
case:
class X { static X x; ... };
X X::x.
The constructor X::x is invoked at pre-execution time. At least that's my understanding and it seems that all the compiler's in our test suite seem to support this behavior.
X::x's static initialization will occur before main(). If X::x requires dynamic intialization, it must occur before the first function following it's definition in that translation unit is invoked. Nothing more is guarranteed. IOW, if the constructor of X requires runtime behavior--opens a file, allocates memory, calculates a number, etc.--then that isn't guarranteed to happen until some function, defined after X::x in the same translation unit, is invoked.
The implementation of BOOST_CLASS_EXPORT depends on static constructors being executed at pre-execution time or for the case of DLLS - up DLL loading
By "pre-execution time," I assume you mean before main() is called. That only applies to static initialization, not dynamic initialization of statics.
Now, on Unix all static initialisers are run when the program is first loaded, so I probably should not care if some other users run into problems.
I don't believe this is a feature of the operating system but rather the compiler. I also believe that the serialization library presumes correctly that they will be invoked a pre-execution time. I never really thought of
Your assumption is ill founded. -- Rob Stewart stewart@sig.com Software Engineer http://www.sig.com Susquehanna International Group, LLP using std::disclaimer;