 
                            ...
The C89 Committee concluded that about the only thing a strictly conforming program can do in a signal handler is to assign a value to a
volatile staticvariable which can be written uninterruptedly and promptly return.
...
 
                            ...
The C89 Committee concluded that about the only thing a strictly conforming program can do in a signal handler is to assign a value to a
volatile staticvariable which can be written uninterruptedly and promptly return.
...