Re: strtold does not set errno when it should
Bruno Haible <[email protected]>
| Newsgroups | gmane.comp.lib.newlib |
|---|---|
| Message-ID | <3071059.SjtNWNUZ6R@omega> |
Hi Corinna, > The code for strtold is almost verbatim taken from > > https://github.com/jwiegley/gdtoa.git > > There haven't been any patches upstream. Probably that's because the code is good enough for ISO C compliance; however, POSIX [1] adds the "ERANGE upon underflow" requirement, whereas ISO C only has an "ERANGE upon overflow" requirement. [1] <https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtod.html> > diff --git a/newlib/libc/stdlib/strtodg.c b/newlib/libc/stdlib/strtodg.c > index 013315946c1b..d6fb26ad3b45 100644 > --- a/newlib/libc/stdlib/strtodg.c > +++ b/newlib/libc/stdlib/strtodg.c > @@ -1091,6 +1091,10 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp, > irv |= STRTOG_Underflow; > } > } > +#ifndef NO_ERRNO > + if (irv & STRTOG_Underflow) > + errno = ERANGE; > +#endif > if (se) > *se = (char *)s; > if (sign) > > which seems to do the trick. But, does it make sense? If not, I'd > really appreciate a patch. I think it goes in the right direction. It can be improved a bit, though: The existing code for overflow is careful to do the errno stuff only when STRTOG_Overflow is being set/added. I.e. keep this overflow/underflow handling out of the main path, in order not to slow down the 99.99% of the cases that don't need it. My attempt to do this would look like the attached patch. Untested. Bruno
strtodg.c.diff
(text/x-patch, 1.9 KB)
diff --git a/newlib/libc/stdlib/strtodg.c b/newlib/libc/stdlib/strtodg.c
index 0133159..743f60b 100644
--- a/newlib/libc/stdlib/strtodg.c
+++ b/newlib/libc/stdlib/strtodg.c
@@ -348,6 +348,9 @@ rvOK (struct _reent *p, double d, FPI *fpi, Long *exp, __ULong *bits, int exact,
if (k > nb || fpi->sudden_underflow) {
b->_wds = inex = 0;
*irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
}
else {
k1 = k - 1;
@@ -362,9 +365,15 @@ rvOK (struct _reent *p, double d, FPI *fpi, Long *exp, __ULong *bits, int exact,
if (carry) {
b = increment(p, b);
inex = STRTOG_Inexhi | STRTOG_Underflow;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
}
else if (lostbits)
inex = STRTOG_Inexlo | STRTOG_Underflow;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
}
}
else if (e > fpi->emax) {
@@ -761,6 +770,9 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
rvb->_x[0] = 0;
*exp = emin;
irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
goto ret;
}
rvb->_x[0] = rvb->_wds = rvbits = 1;
@@ -940,6 +952,9 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
rvb->_wds = 0;
rve = emin;
irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
break;
}
adj0 = dval(adj) = 1.;
@@ -1083,12 +1098,18 @@ _strtodg_l (struct _reent *p, const char *s00, char **se, FPI *fpi, Long *exp,
if (sudden_underflow) {
rvb->_wds = 0;
irv = STRTOG_Underflow | STRTOG_Inexlo;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
}
else {
irv = (irv & ~STRTOG_Retmask) |
(rvb->_wds > 0 ? STRTOG_Denormal : STRTOG_Zero);
if (irv & STRTOG_Inexact)
irv |= STRTOG_Underflow;
+#ifndef NO_ERRNO
+ errno = ERANGE;
+#endif
}
}
if (se)