On Wed, Oct 15, 2025 at 11:50:53AM +0800, Yumei Huang wrote:
> On Wed, Oct 15, 2025 at 7:28 AM David Gibson
> <david@gibson.dropbear.id.au> wrote:
> > On Tue, Oct 14, 2025 at 03:38:34PM +0800, Yumei Huang wrote:
> > > Signed-off-by: Yumei Huang <yuhuang@redhat.com>
[snip]
> > > + * @path: Path to the sysctl file
> > > + * @fallback: Default value if file can't be read
> > > + *
> > > + * Return: Parameter value, fallback on failure
> > > +*/
> > > +long read_file_long(const char *path, long fallback)
> > > +{
> > > +        char buf[32];
> >
> > Rather than just using a semi-arbitrary 32 here, I'd suggest defining
> > a new constant similar to UINT16_STRLEN.  Except that's trickier for a
> > type that doesn't have a known fixed width.  Pity the C library
> > doesn't have constants for these AFAICT.
> 
> I will just define a UINTMAX_STRLEN with (sizeof("2147483647")).

That's not quite right.
 - It should be INTMAX_STRLEN (signed), UINTMAX would be for the
   unsigned version
 - That assumes intmax_t is 32-bit which is probably not the case (it
   will be 64-bit, maybe even 128-bit on modern systems)
 - For signed cases, it's the minimum (negative) value that gives the
   longest possible string (for 32-bit, "-2147483648")

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson