Hook to function

myFun.h

   1: #include <stdio.h>

   2:  

   3: void __cyg_profile_func_enter(void *this_fn, void *call_site)

   4:         __attribute__((no_instrument_function));

   5: void __cyg_profile_func_enter(void *this_fn, void *call_site) {

   6:     printf("Hello I am entering\n");

   7: } /* __cyg_profile_func_enter */

   8: void __cyg_profile_func_exit(void *this_fn, void *call_site)

   9:         __attribute__((no_instrument_function));

  10: void __cyg_profile_func_exit(void *this_fn, void *call_site) {

  11:     printf("Hello, I am exitint\n");

  12: } /* __cyg_profile_func_enter */

  13:  

     main.c

   1: #include <stdio.h>

   2: #include "myfun.h"

   3: void myStartupFun (void) __attribute__ ((constructor));

   4: void myCleanupFun (void) __attribute__ ((destructor));

   5: int foo() {

   6:     return 2;

   7: }

   8: int bar() {

   9:    return 1;

  10: }

  11: int main(int argc, char** argv) {

  12:     int i ,j;

  13:     i = foo();

  14:     j = bar();

  15:     printf("foo=%d bar=%d\n", i, j);

  16:     return 0;

  17: }

 

when you compile this file, please put the myFun.h in the same directory with main.c, and MUST with flag “-finstrument-functions”