-bash-3.2$ cat foo.c
#include <sys/socket.h>

extern ssize_t recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen);

ssize_t foo()
{
  int s;
  void *buf;
  size_t len;
  int flags;
  struct sockaddr *from;
  socklen_t* fromlen;

  return(recvfrom(s, buf, len, flags, from, fromlen));
}

int main(int argc, const char **argv)
{
  return foo();
}


# this fails with these compiler flags:
$ gcc -Wp,-D_FORTIFY_SOURCE=2 -O2 -D_GNU_SOURCE=1 foo.c