c++ - Is it good practice to hide Initialization code "before main"? -

i building c++ library , need initialize opengl context program ( , other default resource objects ). practice ( considering modern c++ semantics ) "hide init. code" in code chunk being called before main ? cannot use static variables because need initialize things in specific order ! (i cannot init texture before openglm or sdl !)

here code :

#include <stdio.h>  #ifdef _msc_ver // msvc / msvc++ 2015  #define ccall __cdecl #pragma section(".crt$xcu",read) #define initializer(f) \    static void __cdecl f(void); \    __declspec(allocate(".crt$xcu")) void (__cdecl*f##_)(void) = f; \    static void __cdecl f(void)  #elif defined(__gnuc__) gcc / g++  #define ccall #define initializer(f) \    static void f(void) __attribute__((constructor)); \    static void f(void)  #endif  static void ccall finalize(void) {     /* king of delete / dispose here : sdl_quit, ... */ }  initializer(initialize) { /*     here startup code ...  */  } 

the standard, section 3.6.2, says non-local static variables may be initialized before first statement of main:

it implementation-defined whether dynamic initialization of non-local variable static storage duration done before first statement of main.

thus, doesn't must be initialized before first statement of main. there no way in c++ enforce constraint initialized before main() called, except static variables defined in same compilation unit main.

the best solution include resource management within main itself:

int main() {     // load resources (housekeeping code)      // real work (applicative code)      // release resources (housekeeping code) } 

if want separate applicative code housekeeping code, commonly used approach use inversion of control (sometimes via template method pattern):

• a separate function or method dedicated applicative or user code
• the function main responsible both doing housekeeping , invoking user-code or applicative-code function or method.

this exemplified below:

// function below expected exist framework // must implemented user int usermain() {     // implement user-code here }  // code below implemented framework // expects user have implemented function usermain int main() {     frameworkdata theframeworkdata;      // framework performs initialization house-keeping here     theframeworkdata.initialize();      // framework invokes user-code (inversion of control)     usermain();      // framework performs clean-up house-keeping here     theframeworkdata.cleanup(); }