Paul Eggert wrote:
> > I propose to change the gradual underflow behaviour of xstrtod
>
> Sounds good. The current behavior with MSVC does make more sense.
Done:
2024-07-24 Bruno Haible <br...@clisp.org>
xstrtod, xstrtold: Don't treat gradual underflow as an error.
* lib/xstrtod.c (XSTRTOD): Upon gradual underflow, return true with
errno = 0.
* lib/xstrtod.h (xstrtod, xstrtold): Update specification.
* tests/test-xstrtod.c (main): For gradual underflow, expect ok &&
errno == 0.
* tests/test-xstrtold.c (main): Likewise.
diff --git a/lib/xstrtod.c b/lib/xstrtod.c
index a9ca7e8d10..7565658e4d 100644
--- a/lib/xstrtod.c
+++ b/lib/xstrtod.c
@@ -57,11 +57,18 @@ XSTRTOD (char const *str, char const **ptr, DOUBLE *result,
else
{
/* Flag overflow as an error.
- Flag gradual underflow as an error.
+ Flag gradual underflow as no error.
Flag flush-to-zero underflow as no error.
In either case, the caller can inspect *RESULT to get more details.
*/
if (val != 0 && errno == ERANGE)
- ok = false;
+ {
+ if (val >= 1 || val <= -1)
+ /* Overflow. */
+ ok = false;
+ else
+ /* Gradual underflow. */
+ errno = 0;
+ }
}
if (ptr != NULL)
diff --git a/lib/xstrtod.h b/lib/xstrtod.h
index 8ceca6c433..f6a1ed888a 100644
--- a/lib/xstrtod.h
+++ b/lib/xstrtod.h
@@ -42,8 +42,7 @@ extern "C" {
NaN true NaN 0
±Infinity true ±HUGE_VAL 0
overflow false ±HUGE_VAL
ERANGE
- gradual underflow [!MSVC] false near zero
ERANGE
- gradual underflow [MSVC] true near zero 0
+ gradual underflow true near zero 0
flush-to-zero underflow true ±0.0
ERANGE
other finite value true value 0
@@ -68,8 +67,7 @@ bool xstrtod (const char *str, const char **ptr, double
*result,
NaN true NaN 0
±Infinity true ±HUGE_VALL 0
overflow false ±HUGE_VALL
ERANGE
- gradual underflow [!MSVC] false near zero
ERANGE
- gradual underflow [MSVC] true near zero 0
+ gradual underflow true near zero 0
flush-to-zero underflow true ±0.0L
ERANGE
other finite value true value 0
diff --git a/tests/test-xstrtod.c b/tests/test-xstrtod.c
index 3464120f1e..e02d97203a 100644
--- a/tests/test-xstrtod.c
+++ b/tests/test-xstrtod.c
@@ -658,36 +658,20 @@ main ()
const char *ptr;
double result = UNINIT;
bool ok = xstrtod (input, &ptr, &result, strtod);
-#if defined _MSC_VER
ASSERT (ok);
-#else
- ASSERT (!ok);
-#endif
ASSERT (0.0 < result && result <= DBL_MIN);
ASSERT (ptr == input + 6);
-#if defined _MSC_VER
ASSERT (errno == 0);
-#else
- ASSERT (errno == ERANGE);
-#endif
}
{
const char input[] = "-1e-320";
const char *ptr;
double result = UNINIT;
bool ok = xstrtod (input, &ptr, &result, strtod);
-#if defined _MSC_VER
ASSERT (ok);
-#else
- ASSERT (!ok);
-#endif
ASSERT (-DBL_MIN <= result && result < 0.0);
ASSERT (ptr == input + 7);
-#if defined _MSC_VER
ASSERT (errno == 0);
-#else
- ASSERT (errno == ERANGE);
-#endif
}
/* Flush-to-zero underflow. */
diff --git a/tests/test-xstrtold.c b/tests/test-xstrtold.c
index b83e78067b..a8788ca100 100644
--- a/tests/test-xstrtold.c
+++ b/tests/test-xstrtold.c
@@ -662,18 +662,10 @@ main ()
const char *ptr;
long double result = UNINIT;
bool ok = xstrtold (input, &ptr, &result, strtold);
-#if defined _MSC_VER
ASSERT (ok);
-#else
- ASSERT (!ok);
-#endif
ASSERT (0.0L < result && result <= LDBL_MIN);
ASSERT (ptr == input + strlen (input));
-#if defined _MSC_VER
ASSERT (errno == 0);
-#else
- ASSERT (errno == ERANGE);
-#endif
}
{
#if LDBL_MAX_EXP > 10000
@@ -684,18 +676,10 @@ main ()
const char *ptr;
long double result = UNINIT;
bool ok = xstrtold (input, &ptr, &result, strtold);
-#if defined _MSC_VER
ASSERT (ok);
-#else
- ASSERT (!ok);
-#endif
ASSERT (-LDBL_MIN <= result && result < 0.0L);
ASSERT (ptr == input + strlen (input));
-#if defined _MSC_VER
ASSERT (errno == 0);
-#else
- ASSERT (errno == ERANGE);
-#endif
}
/* Flush-to-zero underflow. */
