From 186d63a2cc287cfd908342c62f18d123341c20c3 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 6 Mar 2008 21:32:25 +0000
Subject: [PATCH] commit Solaris (round -0.0) workaround

svn: r8906
---
 src/mzscheme/sconfig.h    | 4 ++++
 src/mzscheme/src/number.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/src/mzscheme/sconfig.h b/src/mzscheme/sconfig.h
index e2670cc071..f9caa44cf8 100644
--- a/src/mzscheme/sconfig.h
+++ b/src/mzscheme/sconfig.h
@@ -110,6 +110,8 @@
 # define USE_ON_EXIT_FOR_ATEXIT
 # endif
 
+#define FMOD_CAN_RETURN_POS_ZERO
+
 # ifndef i386
 #  define FLUSH_SPARC_REGISTER_WINDOWS
 # endif
@@ -1216,6 +1218,8 @@
  /* FMOD_CAN_RETURN_NEG_ZERO is fmod() on positive numbers can produce
     a negative zero. */
 
+ /* FMOD_CAN_RETURN_POS_ZERO is fmod() on -0.0 can produce 0.0. */
+
  /* LOG_ZERO_ISNT_NEG_INF defines a version of log that checks for an
     inexact zero argument and return negative infinity. */
 
diff --git a/src/mzscheme/src/number.c b/src/mzscheme/src/number.c
index 17ab4787f3..a187de893f 100644
--- a/src/mzscheme/src/number.c
+++ b/src/mzscheme/src/number.c
@@ -1219,6 +1219,11 @@ sch_round (int argc, Scheme_Object *argv[])
     double i, frac;
     int invert;
 
+#ifdef FMOD_CAN_RETURN_POS_ZERO
+    if (minus_zero_p(d))
+      return d;
+#endif
+
     if (d < 0) {
       d = -d;
       invert = 1;