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From: Ben Bacarisse <ben@bsb.me.uk>
Newsgroups: comp.lang.c
Subject: Re: tcc - first impression. Was: Baby X is bor nagain
Date: Tue, 02 Jul 2024 17:12:47 +0100
Organization: A noiseless patient Spider
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Michael S <already5chosen@yahoo.com> writes:

> On Tue, 02 Jul 2024 16:32:23 +0100
> Ben Bacarisse <ben@bsb.me.uk> wrote:
>
>> Michael S <already5chosen@yahoo.com> writes:
>> 
>> > On Mon, 1 Jul 2024 20:09:24 +0300
>> > Michael S <already5chosen@yahoo.com> wrote:
>> >
>> > As far as I am concerned, the most intriguing feature of tcc is
>> > "Memory and Bound checks". Unfortunately, I was not able to make it
>> > work. It keeps telling me "segmentation error" at first attempt to
>> > dereference argv. Is this feature Linux-only or 32-bit only or some
>> > other type of "only" ?  
>> 
>> The documentation says it should work on x86_64 in Windows.
>> 
>> Can you post the code so we can compare.  With this little program
>> 
>>   #include <stdio.h>
>>    
>>   void f(int *a, int n)
>>   {
>>        printf("a[%d] == %d\n", n, a[n]);
>>   }
>>    
>>   int main(int argc, char **argv)
>>   {
>>        for (int i = 0; i <= argc; i++)
>>             if (argv[i])
>>                  printf("argv[%d] == %s\n", i, argv[i]);
>>             else printf("argv[%d] is a null pointer\n", i);
>>        int a[3];
>>        f(a, 3);
>>   }
>> 
>> I get this output:
>> 
>> $ ./a.out 1
>> argv[0] == ./a.out
>> argv[1] == 1
>> argv[2] is a null pointer
>> 004021b9 : at ???: BCHECK: 0x7ffca6719404 is outside of the region
>> t.c:5: by f
>> t.c:15: by main
>> t.c:5: at f: RUNTIME ERROR: invalid memory access
>> t.c:15: by main    
>> 
>
> I got plain "Segmentation fault".
>
> I it gets me "Segmentation fault" on something as simple as:
>
> #include <stdio.h>
> int main(int argc, char **argv)
> {
>   printf("%p\n", argv[0]);
>   return 0;
> }

Ah.  That looks like a plain "not working" then.  (Presumably you get a
reasonable-looking pointer without the -b option).  What version of tcc?

-- 
Ben.