Call a function before main [duplicate]

Answer 1

If using gcc and g++ compilers then this can be done by using __attribute__((constructor))

eg::
In gcc (c) ::

#include 

void beforeMain (void) __attribute__((constructor));

void beforeMain (void)
{
  printf ("\nbefore main\n");
}

int main ()
{
 printf ("\ninside main \n");
 return 0;
}

In g++ (c++) ::

#include 
using namespace std;
void beforeMain (void) __attribute__((constructor));

void beforeMain (void)
{
  cout<<"\nbefore main\n";
}

int main ()
{
  cout<<"\ninside main \n";
  return 0;
}