How to write generic hook for functions in C?

Question

I want to write a hook function that is called whenever a function is called in my program to gather some statistics about the arguments of the function. For example:

void hook(function f, ...){
    //some statistics here
    f(...);
}
int main(){
    foo(1, 2);
}

So instead of calling foo directly, it will call hook instead with foo as its first argument and 1, 2 as extra arguments.

Is there anything similar to this in C? Can I achieve this goal in C in any other way?

Answer 1

Macros can be (ab)used to achieve this in a simplistic way:

void foo( int , int );

void Hook( int a , int b )
{
    //do whatever
    foo( a , b );
} 

#define foo( a , b ) Hook( a , b )

int main( void )
{
    foo( 1 , 2 );
}

Note that this is error prone and requires careful writing.

Answer 2

Perhaps this is what you are looking for?

typedef enum FunctionPointerType_E
   {
   FPT_Int_IntInt = 1
   } FunctionPointerTypes_T

int foo(
      int a,
      int b
      )
   {
   return(a+b);
   }

void hook(
      FunctionPointerTypes_T fpt,
      void (*function)(void),
      ...
      )
   {
   int rCode;
   int (*fp_Int_IntInt)(int, int);

   switch(fpt)
     {
     case FPT_Int_IntInt:
        fp_Int_IntInt = (int(*)(int, int))function;
        rCode=(*fp_Int_IntInt)(1,2);
     ...
     }

   return;
   }

void CallFooByRefrence(void)
   {
   hook(FPT_Int_IntInt, (void(*)(void))foo, ...);
   return;
   }