c++ - DLL design : the DLL needs to access some of the application functions/data -

i have dll bunch of functions. far, good, that's dll for. but, functions in dll need call functions (or access data) application loaded dll.

app.exe :

std::vector<someclass> objectslist; bool foo(void) {     ... } loadlibrary( "something.dll" );   

something.dll :

__declspec(dllexport) void somefunction(void) {     if ( foo() )     {         objectslist[2].someattr = 1;     } } 

for know, dll code in not correct because dll cannot know foo or objectslist @ linking. so, way see :

something.dll :

typedef bool footype(void); footype* pfoofunc; __declspec(dllexport) void setfoo(footype* fooptr) {     pfoofunc = fooptr; } __declspec(dllexport) void somefunction(void) {     if ( (*pfoofunc)() )     {         ... _same thing objectslist_         } } 

app.exe :

loadlibrary( "something.dll" );   setfoo = getprocaddress(...); setfoo(&foo); 

am right or there more elegant way kind of stuff ?
solutions here : a dll need access symbols of application still interested in discussion kind of design.

thanks

there 2 common solutions: first dll use sort of callback; second put functions , data shared between root , dll(s) separate dll of own.