Re: `SCM_MAKE_CHAR ()' signedness issue

[Ken Raeburn]

On Aug 15, 2009, at 08:00, Ludovic Courtès wrote:
Hello,
We still have troubles with the `(scm_t_int32) (x) < 0' test in
`SCM_MAKE_CHAR ()':

--8<---------------cut here---------------start------------->8---
l...@gcc54:~/guile-1.9.1/+build$ cat ,,t.c
int
foo (unsigned char x)
{
 return (((int)x) < 0 ? 1 : -1);
}
l...@gcc54:~/guile-1.9.1/+build$ gcc -Wall -c ,,t.c
,,t.c: In function ‘foo’:
,,t.c:4: warning: comparison is always false due to limited range of  
data type

In the case of SCM_MAKE_CHAR, both actions give identical results for  
an input of 0, so I think just testing "x <= 0" will silence the  
warning without changing the behavior.

There's always the inline-function approach, too.

Ken