Re: c++/7538: Constructors of static members are not called always

[nathan@gcc.gnu.org]

Synopsis: Constructors of static members are not called always

State-Changed-From-To: analyzed->closed
State-Changed-By: nathan
State-Changed-When: Wed Sep 25 03:52:09 2002
State-Changed-Why:
    not a bug.
    [3.6.2]/3 says dynamic initialization may be delayed, but
    must be done before the first use of any function or object
    defined in the same TU as the object to be initialized.
    
    The TU which defines ClassA::m_stClass is classA.cpp. The
    main program uses ClassA::ClassA, ClassA::~ClassA and
    ClassA::returns_five. All those are inline functions
    defined in classA.hpp. [3.2]/3 says an inline function
    shall be defined in every TU in which it is used. As
    those inline functions are defined in main.cpp.
    
    Hence we never use anything defined in the TU classA.cpp,
    and so never need to initialize classA::m_stClass.
    
    The reason you see different behaviours with a library
    vs explicit classA.o, is that in the latter case the linker
    is forced to include classA.o in the final executable, that
    pulls in the static ctor function for that object file.
    With a library, classA.o is only pulled in, if something explicitly references an object/function defined within
    it. Should that happen then all of classA.o is pulled in,
    which will include the static ctor function.
    
    The standard permits this.

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