[Coco] os9 intercept call from C

[Walter Zambotti]

I got around the Ansi front end issue by simply truncating the name to 8
characters 'intercep' and it now compiles and links and I can still use
Ansi syntax.

Walter

On 2020-04-19 00:44, Walter Zambotti wrote:
> Opps nine characters long!!!
>
> Which is exactly when the Ansi front end will start converting long
> variable names to hashes.
>
> On 2020-04-19 00:41, Walter Zambotti wrote:
>> That's what I have trying to say guys.
>>
>> The intercept function is not in the standard library as expected.
>>
>> At least for me if I comment out my intercept function then it fails to
>> link with unresolved reference to intercept.
>>
>> Figured out what is going wrong with the missing intercept library function.
>>
>> An rdump shows it is in the library.
>>
>> The problem starts when compiling with Ansi front end.  It converts the
>> reference to _hexvalue which I can see on the _ntbl file.
>>
>> Which it should not do.  Especially since 'intercept' is only 8
>> characters long.
>>
>> I suppose that's another bug in the Ansi front end.
>>
>> I reverted the code back to K&R and it compiles and links with no problem.
>>
>> Thanks guys
>>
>> Walter
>>
>> On 2020-04-18 23:38, Alex Evans wrote:
>>> Largely ignoring the fact that the above code uses ANSI syntax and the
>>> only MW C Compiler I am aware of for the CoCo uses K&R. If you use the
>>> provided intercept function in the library, the function to be called
>>> is a normal C function which takes an integer as a parameter (no RTI).
>>> If you are going to finable about directly using F$Icpt to set you
>>> trap, it needs to return using RTI. In addition, you need to set the
>>> pointer to the routine's storage area in U, but in the case of the
>>> function you have provided, it does not appear to need any storage
>>> space, so the fact you didn't set U shouldn't be a problem.
>>>
>>> I would think (untested) the answer would be:
>>> int catchall();
>>>
>>> int intflag=0;
>>>
>>> main(argc, argv)
>>> int argc;
>>> char *argv[];
>>> {
>>>   intercept(catchall);
>>>   while (!intrlag) {
>>>     pause();
>>>     write(1, "*", 1);
>>>   }
>>> }
>>>
>>> catchall(sig)
>>> int sig;
>>> {
>>>   intfrag=sig==0x03;
>>> }
>>>
>>> If your really, really want to directly use the system call, you need
>>> to also pull the signal number from somewhere. The routine expexted by
>>> F$cpt is a machine code routine, and sig will probably not be passed
>>> on the stack in the manner that MW C expects, so you need to figure
>>> out where it would be.
>>>