--- a/src/sysdep.cc
+++ b/src/sysdep.cc
@@ -28,6 +28,13 @@
 #include <stdlib.h>
 
 #include "error.h"
+#include "sysdep.h"
+
+// Octave's idea of infinity.
+double octave_Inf;
+
+// Octave's idea of not a number.
+double octave_NaN;
 
 #if defined (__386BSD__) && defined (HAVE_FLOATINGPOINT_H)
 #include <floatingpoint.h>
@@ -58,6 +65,53 @@
 }
 #endif
 
+static void
+octave_ieee_init (void)
+{
+#if defined (HAVE_ISINF) || defined (HAVE_FINITE)
+
+// Some version of gcc on some old version of Linux used to crash when
+// trying to make Inf and NaN.
+
+#if defined (HAVE_INFINITY)
+  octave_Inf = infinity ();
+#else
+#ifdef linux
+  octave_Inf = HUGE_VAL;
+#else
+  double tmp = 1e+10;
+  octave_Inf = tmp;
+  for (;;)
+    {
+      octave_Inf *= 1e+10;
+      if (octave_Inf == tmp)
+	break;
+      tmp = octave_Inf;
+    }
+#endif
+#endif
+
+#if defined (HAVE_QUIET_NAN)
+  octave_NaN = quiet_nan ();
+#else
+#ifdef linux
+  octave_NaN = NAN;
+#else
+  octave_NaN = octave_Inf / octave_Inf;
+#endif
+#endif
+
+#else
+
+// This is sort of cheesy, but what can we do, other than blowing it
+// off completely, or writing an entire IEEE emulation package?
+
+  octave_Inf = DBL_MAX;
+  octave_NaN = DBL_MAX;
+
+#endif
+}
+
 void
 sysdep_init (void)
 {
@@ -69,6 +123,8 @@
 #ifdef NeXT
   NeXT_init ();
 #endif
+
+  octave_ieee_init ();
 }
 
 /*