Re: How to type braces for computed gotos

federation2005@netzero.com wrote:


(snip)


> There is one feature the compiler tests for that I assume the language also
> has in it that I haven't seen much of before: the computed goto. What's I
> don't quite understand how the branches are being typed. A computed goto
> inside a void routine has the branches typed (void *), with the individual
> items accessed in effect as references to (void *).


(snip)


> [That's an extension. In standard C, you can only goto a label. -John
> Perhaps it's similar to this GCC extension
> https://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels-as-Values]


In standard C you can only goto label constants.


In PL/I you can goto label constants or variables.


In standard C, you should be able to make an array of jmp_buf and
then longjmp() to an element of the array. However, you can only
longjmp() to an element once.


I don't know that I ever tried, but I believe you can GOTO a PL/I
label variable more than once, as long as it still makes logical
sense to do it. (That is, it isn't inside a procedure that has
already returned.)


-- glen
[Ugh. -John]

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