Issue #7070: Fix problem with builtin round function for large odd
integer arguments. Also fixes the sign of round(-0.0).
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 015e16b..87da3c9 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2120,7 +2120,7 @@
static PyObject *
builtin_round(PyObject *self, PyObject *args, PyObject *kwds)
{
- double number;
+ double number, abs_number, abs_result;
double f;
int ndigits = 0;
int i;
@@ -2137,10 +2137,14 @@
number /= f;
else
number *= f;
- if (number >= 0.0)
- number = floor(number + 0.5);
- else
- number = ceil(number - 0.5);
+
+ /* round `number` to nearest integer, rounding halves away from zero */
+ abs_number = fabs(number);
+ abs_result = floor(abs_number);
+ if (abs_number - abs_result >= 0.5)
+ abs_result += 1.0;
+ number = copysign(abs_result, number);
+
if (ndigits < 0)
number *= f;
else