From e01925c580bf11da70dc0faed8668c09cffa0d40 Mon Sep 17 00:00:00 2001
From: Nick Bowler <nbowler@draconx.ca>
Date: Wed, 13 Oct 2010 18:38:54 -0400
Subject: [PATCH] fenv: Add appropriate #ifdef's to rounding direction helpers.

An implementation need not support all of the rounding modes, so only
compile in support for those that are available.
---
 Data/Floating/Environment.hs | 20 ++++++++++----------
 cfloat.c                     | 20 ++++++++++++++++++--
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/Data/Floating/Environment.hs b/Data/Floating/Environment.hs
index c90ee11..ccc38d8 100644
--- a/Data/Floating/Environment.hs
+++ b/Data/Floating/Environment.hs
@@ -70,10 +70,14 @@ import Debug.Trace
 import Foreign.C
 import Foreign
 
-foreign import ccall unsafe "set_roundmode"
-    set_roundmode :: CInt -> IO CInt
-foreign import ccall unsafe "get_roundmode"
-    get_roundmode :: IO CInt
+foreign import ccall unsafe "fenv_set_roundmode"
+    fenv_set_roundmode :: CInt -> IO CInt
+foreign import ccall unsafe "fenv_get_roundmode"
+    fenv_get_roundmode :: IO CInt
+foreign import ccall unsafe "fenv_test_excepts"
+    fenv_test_excepts :: IO CUInt
+foreign import ccall unsafe "fenv_raise_excepts"
+    fenv_raise_excepts :: CUInt -> IO CInt
 
 foreign import ccall unsafe "fegetenv"
     c_fegetenv :: Ptr FEnvState -> IO CInt
@@ -81,10 +85,6 @@ foreign import ccall unsafe "fesetenv"
     c_fesetenv :: Ptr FEnvState -> IO CInt
 foreign import ccall unsafe "feholdexcept"
     c_feholdexcept :: Ptr FEnvState -> IO CInt
-foreign import ccall unsafe "fenv_test_excepts"
-    fenv_test_excepts :: IO CUInt
-foreign import ccall unsafe "fenv_raise_excepts"
-    fenv_raise_excepts :: CUInt -> IO CInt
 
 data RoundingMode = ToNearest | Upward | Downward | TowardZero
     deriving (Show, Read, Enum, Bounded)
@@ -227,12 +227,12 @@ unsafeRaiseExceptions ex = do
 
 unsafeSetRoundingMode :: RoundingMode -> IO ()
 unsafeSetRoundingMode mode = do
-    rc <- set_roundmode (fromIntegral (fromEnum mode))
+    rc <- fenv_set_roundmode (fromIntegral (fromEnum mode))
     unless (rc == 0) $ fail "Error setting rounding mode"
 
 getRoundingMode :: IO RoundingMode
 getRoundingMode = do
-    rc <- get_roundmode
+    rc <- fenv_get_roundmode
     unless (rc >= 0) $ fail "Error getting rounding mode"
     return . toEnum . fromIntegral $ rc
 
diff --git a/cfloat.c b/cfloat.c
index 58af4b9..6fd13d5 100644
--- a/cfloat.c
+++ b/cfloat.c
@@ -104,23 +104,31 @@ int float_compare(float a, float b)
 	return -1;
 }
 
-int set_roundmode(int mode)
+int fenv_set_roundmode(int mode)
 {
 	int cmode;
 
 	switch (mode) {
+#ifdef FE_TONEAREST
 	case 0:
 		cmode = FE_TONEAREST;
 		break;
+#endif
+#ifdef FE_UPWARD
 	case 1:
 		cmode = FE_UPWARD;
 		break;
+#endif
+#ifdef FE_DOWNWARD
 	case 2:
 		cmode = FE_DOWNWARD;
 		break;
+#endif
+#ifdef FE_TOWARDZERO
 	case 3:
 		cmode = FE_TOWARDZERO;
 		break;
+#endif
 	default:
 		return -1;
 	}
@@ -128,19 +136,27 @@ int set_roundmode(int mode)
 	return fesetround(cmode);
 }
 
-int get_roundmode(void)
+int fenv_get_roundmode(void)
 {
 	int cmode = fegetround();
 
 	switch (cmode) {
+#ifdef FE_TONEAREST
 	case FE_TONEAREST:
 		return 0;
+#endif
+#ifdef FE_UPWARD
 	case FE_UPWARD:
 		return 1;
+#endif
+#ifdef FE_DOWNWARD
 	case FE_DOWNWARD:
 		return 2;
+#endif
+#ifdef FE_TOWARDZERO
 	case FE_TOWARDZERO:
 		return 3;
+#endif
 	default:
 		return -1;
 	}
-- 
2.11.4.GIT