isascii(3) macros and casts

[Alejandro Colomar]

Hi Andreas,

On Wed, Dec 11, 2024 at 03:03:00PM +0100, Andreas Schwab wrote:
> On Dez 11 2024, Alejandro Colomar wrote:
> 
> > 	inline bool
> > 	my_isdigit(int c)
> > 	{
> > 		unsigned char  uc = c;
> >
> > 		return isdigit(uc);
> 
> This is wrong for EOF.

Is it?  EOF is -1, which is converted to 255, which is not a digit.

	alx@devuan:~/tmp/glibc$ cat isdigit.c 
	#include <ctype.h>
	#include <stdio.h>

	int
	my_isdigit(int c)
	{
		unsigned char  uc = c;

		return isdigit(uc);
	}

	int
	main(void)
	{
		printf("%d\n", isdigit((unsigned char) EOF));
		printf("%d\n", my_isdigit(EOF));
	}
	alx@devuan:~/tmp/glibc$ cc -Wall -Wextra isdigit.c 
	alx@devuan:~/tmp/glibc$ ./a.out 
	0
	0

This experiment seems to say it's ok.

Cheers,
Alex

-- 
<https://www.alejandro-colomar.es/>
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