c++ - Is there a way to call an initialization function only when specific class template (specialization) is instantiated? -

i'm designing wrapper on various computational functionality. of underlying backends require init functions called before other api calls made. use static variable initialized before main, , wrap in function described here can catch errors produced during initialization.

i wonder if there better way handle this. note there never instance of class template, either typedef or static member.

to address problem of initializing api specializations, , of initializing once, i'd this:

#include <iostream>  template <typename t> struct wrapper {     // class statically instantiated     struct ctorclass     {         ctorclass()         {             std::cout << "init\n";         }     };      static ctorclass static_ctor;      static void compute1(){}     static void compute2(){}  };  // definition template static member cons template <typename t> typename wrapper<t>::ctorclass wrapper<t>::static_ctor;  struct needinit{};  // have use static_ctor in every funcition of template <> void wrapper<needinit>::compute1() {     static_ctor; }  template <> void wrapper<needinit>::compute2() {     static_ctor; }  int main() {     wrapper<int>::compute1();     wrapper<int>::compute2();     wrapper<needinit>::compute1();     wrapper<needinit>::compute2(); } 

sadly, way have use static_ctor in every function specialization belongs wrapper<needinit> class. wouldn't need check initialization have been called.

then, catch errors said.