--- a/liboctave/lo-ieee.h
+++ b/liboctave/lo-ieee.h
@@ -23,6 +23,10 @@
 #if !defined (octave_liboctave_ieee_h)
 #define octave_liboctave_ieee_h 1
 
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
 // Octave's idea of infinity.
 extern double octave_Inf;
 
@@ -32,14 +36,30 @@
 // Octave's idea of a missing value.
 extern double octave_NA;
 
-extern void octave_ieee_init (void);
+void octave_ieee_init (void);
 
-extern "C" int lo_ieee_is_NA (double);
-extern "C" int lo_ieee_is_NaN_or_NA (double);
+int lo_ieee_is_NA (double);
+int lo_ieee_is_NaN_or_NA (double);
 
 #if defined (SCO)
-extern "C" int isnan (double);
-extern "C" int isinf (double);
+int isnan (double);
+int isinf (double);
+#endif
+
+extern int lo_ieee_hw;
+extern int lo_ieee_lw;
+
+typedef union
+{
+  double value;
+  unsigned int word[2];
+} lo_ieee_double;
+
+#define LO_IEEE_NA_HW 0x7ff00000
+#define LO_IEEE_NA_LW 1954
+
+#ifdef	__cplusplus
+}
 #endif
 
 #endif