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From: Thiago Adams <thiago.adams@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: do { quit; } else { }
Date: Fri, 4 Apr 2025 17:43:55 -0300
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Em 4/4/2025 5:39 PM, Kaz Kylheku escreveu:
> On 2025-04-04, Kaz Kylheku <643-408-1753@kylheku.com> wrote:
>> On 2025-04-04, Thiago Adams <thiago.adams@gmail.com> wrote:
>>>     What do you think of this control block?
>>>
>>>     do
>>>     {
>>>        FILE f = fopen("file.txt", "r");
>>>
>>>        if (f == NULL) quit; /*goes to else part*/
>>>
>>>        /*success here*/
>>>        for (int i =0; i < 10; i++){
>>>            ...
>>>            if (error) quit;
>>>        }
>>>
>>>     }
>>>     else
>>>     {
>>>        /*some error*/
>>>     }
>>
>>
>> The else part might need access to some local variables
>> in the main part.
>>
>>    do {
>>       char *name = calculate_path(PATH_PREFIX "/", name, ".txt");
>>       FILE *f = fopen(...)
>>
>>       if (!f)
>>         quit;
>>       ...
>>    }
>>    else
>>    {
>>       printf("unable to open %s\n", name);
>>       ...
>>    }
>>
>> If you make that work, you're creating scope wormholes between
>> disjoint curly braces, which is not allowed if youre name isn't
>> Bjarne Stroustrup.
> 
> How about: do/else if/else if/else with argument passing to first
> clause whose signature can take the argument list:
> 
>   do {
>     ...
>     quit("rage"); // goes to (char *arg)
>     ...
>     quit(42);     // goes to (int arg)
>     ...
>   }
>   else if (char *arg)  // or just else? multiple elses on do, why not.
>   {
>   }
>   else (int arg)
>   {
>   }
> 
> Friday `f`noons, eh?
> 


In this case.. I think try throw catch is suitable.

try{
   throw 1;
}
catch (int e){
}

try{
   throw;
}
catch {
}

but...the pattern I use is..
{
  int error = 0;
  try{
    error = ...
    if (error != 0) throw;
  }
  catch {
  }
  return error;
}