Robert Wilhelm : oleaut32: Fix VarR8Round for negative numbers.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 0d6c905add980db7902164d59576977d41b9230d
URL:    https://gitlab.winehq.org/wine/wine/-/commit/0d6c905add980db7902164d59576977...

Author: Robert Wilhelm <robert.wilhelm(a)gmx.net>
Date:   Tue Nov 28 21:28:33 2023 +0100

oleaut32: Fix VarR8Round for negative numbers.

Floats with fractional part 0.5000 should be rounded to next even number.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55185

---

 dlls/oleaut32/tests/vartype.c | 7 +++++++
 dlls/oleaut32/vartype.c       | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/dlls/oleaut32/tests/vartype.c b/dlls/oleaut32/tests/vartype.c
index 36b04aead81..9426272d7be 100644
--- a/dlls/oleaut32/tests/vartype.c
+++ b/dlls/oleaut32/tests/vartype.c
@@ -2716,6 +2716,13 @@ static void test_VarR8Round(void)
   MATHRND(1.4999, 0); EXPECT(1);
   MATHRND(1.5000, 0); EXPECT(2);
   MATHRND(1.5001, 0); EXPECT(2);
+
+  MATHRND(-0.4999, 0); EXPECT(0);
+  MATHRND(-0.5000, 0); EXPECT(0);
+  MATHRND(-0.5001, 0); EXPECT(-1);
+  MATHRND(-1.4999, 0); EXPECT(-1);
+  MATHRND(-1.5000, 0); EXPECT(-2);
+  MATHRND(-1.5001, 0); EXPECT(-2);
 }
 
 /*
diff --git a/dlls/oleaut32/vartype.c b/dlls/oleaut32/vartype.c
index 7dd6cb8c4a6..d51cee3ee82 100644
--- a/dlls/oleaut32/vartype.c
+++ b/dlls/oleaut32/vartype.c
@@ -3379,7 +3379,7 @@ HRESULT WINAPI VarR8Round(double dblIn, int nDig, double *pDblOut)
   else if (fract >= 0.0)
     dblIn = whole;
   else if (fract == -0.5)
-    dblIn = whole - fmod(whole, 2.0);
+    dblIn = whole + fmod(whole, 2.0);
   else if (fract > -0.5)
     dblIn = whole;
   else