smehta@SumitMehta-EeePC:~$ gcc signals.c
signals.c: In function ‘main’:
signals.c:49: error: redefinition of ‘i’
signals.c:45: error: previous definition of ‘i’ was here
signals.c:49: error: ‘for’ loop initial declaration used outside C99 mode
signals.c:51: error: invalid lvalue in unary ‘&’