The syntax looks like this:
sigjmp_buf context;
sigsetjmp(context, 1);
siglongjmp(context, 1);
The only real difference is adding the argument "1" to sigsetjmp. The second argument to both can be simply the constant "1".
The reason behind this is sort of complicated and will be discussed in class. It is possible to design this so you do NOT need this - and probably that is the cleaner implementation - but I will not require you to do so. Use the calls above and you should be good to go. Also, you need to be sure you have allowed enought stack space - My program is running with 65536 (64K) as my stack space increment.