#include <iostream>
                                                                                
int main() {
  int *t = new int();
                                                                                
  delete (t);
  delete (t);
                                                                                
}

[ 26 ] 9.13-15 -: setenv MALLOC_CHECK_ 1
[ 37 ] 9.13-15 -: ./test
malloc: using debugging hooks
free(): invalid pointer 0x80498e8!