Auto-wrapping functions wrapper in C

Question

I want to create a wrapper for a function with a specific body that calls a wrapped function.

How can I get from this:

int foo (int arg)
{ 
   do_something(arg);
}

Something equivalent to this:

int foo (int arg)
{
   always_do_this();
   real_foo(arg);
}
int real_foo (int arg)
{ 
   do_something(arg);
}  

I have to do the conversion automatically, and it must be independent of the signature and at compile time.

How can i do this?

Answer 1

I had to refuse to install the shell in the function declaration, the solution was to install shells when calling the function using compound statements. Below are two macros that I created for this, one of them refers to calls that return void, the other with any call that returns a value:

#define PROFILE_VOID(call) \
({ \
  hal_time_t stop, start; \
  hal_getTime(&start); \
  call; \
  hal_getTime(&stop); \
  __PROFILE_PRINT(call, hal_secondsElapsed_d(&stop, &start)); \
})

#define PROFILE(call) \
({ \
  typeof(call) __ret; \
  hal_time_t stop, start; \
  __profile_nested_cnt++; \
  hal_getTime(&start); \
  __ret = call; \
  hal_getTime(&stop); \
  __profile_nested_cnt--; \
  __PROFILE_PRINT(call, hal_secondsElapsed_d(&stop, &start)); \
  __ret; \
})

Usage example:

PROFILE_VOID(func_returning_void(arg, arg2)); //Void func
PROFILE(other_funcs());  // Any non void func
PROFILE(x = func(x, y, z));  //Any statement
x = PROFILE(func(x, y, z));  //Same as previous
if (PROFILE(func()) == 0) { } //Inside conditionals
if (PROFILE(func() == 0)) { } //Same as previous

Answer 2

, :

#define CREATE_FUNC_WRAPPER(NAME, ARG)      \
    int NAME(ARG arg) {         \
        real_##NAME(arg);       \
    }

int real_foo(int a) {
    printf("real_foo speaking: %d\n", a);
}

CREATE_FUNC_WRAPPER(foo, int)

int main() {
    foo(1);
}

, .