在 2012-12-11二的 10:52 +0100，Stefan Hajnoczi写道：
> On Fri, Dec 07, 2012 at 11:49:49AM +0800, liguang wrote:
> > if value to be translated is larger than INT64_MAX,
> > this function will not be convenient for caller to
> > be aware of it, so change a little for this.
> >
> > Signed-off-by: liguang <lig.f...@cn.fujitsu.com>
> > ---
> > cutils.c | 5 +++--
> > 1 files changed, 3 insertions(+), 2 deletions(-)
>
> I don't understand what this patch is supposed to do.
little change to let the caller know the translated value overflow
>
> Why change the type of mul from double to int64_t?
mul is multiplier generated by suffix_mul(return value type int64_t)
so double is incorrect.
>
> Are you using retval = 0 as a special value to indicate overflow?
yes, just an indicator for caller, not so normal return value
> Then
> the new return value should be documented. But it would be better to
> change the function to return -errno values instead of 0/-1 so the
> caller knows the reason for specific failure cases (e.g. -E2BIG).
because of 'retval = 0' is only a hacking way to reflect an illegal
translated value, does it have to act in such an 'official' way?
>
> Should the val < 0 case be checked earlier in the function? It seems
> like a different failure case then INT64_MAX overflow.
maybe, but I think no one interested in difference between
under-overflow
>
> > diff --git a/cutils.c b/cutils.c
> > index 4f0692f..8905b5e 100644
> > --- a/cutils.c
> > +++ b/cutils.c
> > @@ -219,11 +219,11 @@ static int64_t suffix_mul(char suffix, int64_t unit)
> > int64_t strtosz_suffix_unit(const char *nptr, char **end,
> > const char default_suffix, int64_t unit)
> > {
> > - int64_t retval = -1;
> > + int64_t retval = -1, mul;
> > char *endptr;
> > unsigned char c;
> > int mul_required = 0;
> > - double val, mul, integral, fraction;
> > + double val, integral, fraction;
> >
> > errno = 0;
> > val = strtod(nptr, &endptr);
> > @@ -246,6 +246,7 @@ int64_t strtosz_suffix_unit(const char *nptr, char
> > **end,
> > goto fail;
> > }
> > if ((val * mul >= INT64_MAX) || val < 0) {
> > + retval = 0;
> > goto fail;
> > }
> > retval = val * mul;
> > --
> > 1.7.2.5
> >
> >
--
regards!
li guang
