Investigation: init order of static template member fields
indicates rather questionable behaviour. The standard demands a templated static field to be defined before first odr-use. IIRC, it even demands a static field to be initialised prior to use in a ctor. But here the definition of the templated static member field is dropped off even after the definition of another static field, which uses the (templated) Front-end-class in its initialiser.
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102
research/try.cpp
102
research/try.cpp
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@ -37,24 +37,17 @@
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// 11/17 - detect generic lambda
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// 12/17 - investigate SFINAE failure. Reason was indirect use while in template instantiation
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// 03/18 - Dependency Injection / Singleton initialisation / double checked locking
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// 04/18 - investigate construction of static template members
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/** @file try.cpp
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** Rework of the template lib::Depend for singleton and service access.
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** The (now for the third time rewritten) dependency factory can be configured to yield
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** a subclass singleton, or to bind to an external service. Lazy initialisation relies on
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** Double Checked Locking, which we need switch to C++11 Atomics in order to be correct
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** (in theory). The impact of this initialisation guard should be investigated by benchmark.
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* Investigation: static initialisation order -- especially of static template member fields
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*/
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typedef unsigned int uint;
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#include "lib/format-cout.hpp"
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#include "lib/depend.hpp"
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#include "lib/depend-inject.hpp"
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//#include "lib/meta/util.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/util.hpp"
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@ -64,54 +57,73 @@ typedef unsigned int uint;
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cout << "Probe " << STRINGIFY(_XX_) << " ? = " << _XX_ <<endl;
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namespace error = lumiera::error;
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using lib::Depend;
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using lib::DependInject;
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//////////////////////////////////////////////////////////////////////////Microbenchmark
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#include "lib/test/microbenchmark.hpp"
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using lib::test::microbenchmark;
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//////////////////////////////////////////////////////////////////////////(End)Microbenchmark
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#include "include/lifecycle.h"
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#include "lib/test/testoption.hpp"
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#include "lib/test/suite.hpp"
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using lumiera::LifecycleHook;
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using lumiera::ON_GLOBAL_INIT;
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using lumiera::ON_GLOBAL_SHUTDOWN;
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///////////////////////////////////////////////////////Usage
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class BlackHoleService
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: util::NonCopyable
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template<typename T>
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class Factory
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{
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volatile int theHole_ = rand() % 1000;
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public:
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int readMe() { return theHole_; }
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T val;
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Factory()
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: val{}
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{
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cout << "Factory-ctor val="<<val<<endl;
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}
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};
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template<typename T>
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class Front
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{
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public:
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static Factory<T> fac;
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Front()
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{
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cout << "Front-ctor val="<<fac.val<<endl;
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fac.val += 100;
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}
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T&
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operate ()
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{
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cout << "Front-operate val="<<fac.val<<endl;
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++ fac.val;
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return fac.val;
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}
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};
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template<typename T>
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Factory<T> Front<T>::fac;
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namespace {
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Front<int> front;
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int
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staticFun()
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{
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cout << "staticFun"<<endl;
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return front.operate() += 10;
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}
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int global_int = front.operate();
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}
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int
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main (int, char**)
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{
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std::srand(std::time(nullptr));
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LifecycleHook::trigger (ON_GLOBAL_INIT);
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Depend<BlackHoleService> mystery;
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cout << "make-Front<int>..."<<endl;
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Front<int> fint;
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thread_local int64_t cnt = 0;
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int& i = fint.operate();
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cout << "main: val="<<i<<endl;
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cout << "main: staticFun..."<<staticFun()<<endl;
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cout << "global_int.......="<<global_int<<endl;
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cout << microbenchmark<8> ([&]()
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{
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cnt += mystery().readMe();
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}
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,50000000)
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<< endl;
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LifecycleHook::trigger (ON_GLOBAL_SHUTDOWN);
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cout << "\n.gulp.\n";
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return 0;
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