longjmp 用法

 #include <setjmp.h> jmp_buf env; int main (void)
    { if (setjmp (env))
        {
            ... handle error ...
        } while (1)
        {
           ... main processing loop which calls foo() some where ...
        }
    }

    ... void foo (void)
    {
        ... blah, blah, blah ... if (err)
        { longjmp (env, 1);
        }
    }