C语言库函数 setjmp

#include
#include
#include

jmp_buf jumper;
void subroutine()
{
        longjmp(jumper,1);
        printf("never to be execute \n");
}
int main(int argc ,char ** argv)
{
        int value;
        value =setjmp(jumper);
        if(value!=0)
        {
                printf("Longjmp with value=%d\n",value);
                exit(value);
        }
        printf("About to call subroutine...\n");
        subroutine();

        return 0;
}