[gccsdk] GCC 4.7.4 Rel 4: isblank()

Lee Noar lee.noar at sky.com
Fri Jul 10 08:08:50 PDT 2020


On 09/07/2020 11:44, Duncan Moore wrote:
> First of all, many thanks to everyone who's contributed to the latest
> release.
> 
> There are a couple of issues with isblank():
> 
> 1) In <ctype.h>, isblank() is incorrectly defined the same as isspace():
>  �� #� define isspace(c) (__ctype[(int) (c)] & ___ctype_white)
>  �� #� define isblank(c) (__ctype[(int) (c)] & ___ctype_white)
> 
> 2) When there's a function pointer to isblank(), I get a link failure:
> "undefined reference to `isblank'".
> 
> So this program:
> 
> #include <stdio.h>
> #include <ctype.h>
> int main(void) {
>  � int (*space)(int)=isspace;
>  � int (*blank)(int)=isblank;������ // Fails to link.
> 
>  � printf("%i\n",!!isspace('\n'));
>  � printf("%i\n",!!space('\n'));
> 
>  � printf("%i\n",!!isblank('\n'));
>  � printf("%i\n",!!blank('\n'));��� // Fails to link.
> 
>  � return 0;
> }
> 
> should give:
> 
> 1
> 1
> 0
> 0
> 
> whereas, if the 2 lines with comments are removed, I get:
> 
> 1
> 1
> 1
> 
> and it fails to link otherwise.

Ok, thanks for that, I can see that I failed to provide an isblank()
function to go with the macro.
Some googling shows that isblank() should return true only for a space
character or a tab. I could implement this easily in the function (and
remove the macro) by testing the characters directly, e.g.:

return (c == ' ' || c == '\t');

however, that doesn't go via the territory module like the other
ctype functions/macros do. On the other hand, the territory
module doesn't seem to distinguish this particular combination,
so I may have to cheat as above.
Does anyone know different or do I go with the cheat?

Thanks,
Lee.



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