--- perl-5.8.7/perl.h.IOC_SIZE	2005-05-07 16:11:45.000000000 -0400
+++ perl-5.8.7/perl.h	2005-10-25 16:56:10.000000000 -0400
@@ -2508,11 +2508,17 @@
 
 #ifndef IOCPARM_LEN
 #   ifdef IOCPARM_MASK
-	/* on BSDish systes we're safe */
+	/* on BSDish systems we're safe */
 #	define IOCPARM_LEN(x)  (((x) >> 16) & IOCPARM_MASK)
 #   else
-	/* otherwise guess at what's safe */
-#	define IOCPARM_LEN(x)	256
+#	ifdef _IOC_SIZE
+		/* on Linux systems we're safe */
+#		define IOCPARM_LEN(x) _IOC_SIZE(x)
+#	else
+		/* otherwise guess at what's safe (we're UNSAFE!) */
+#		warning "unsafe assumption of IOCPARM_LEN=256"
+#		define IOCPARM_LEN(x)	256
+#	endif
 #   endif
 #endif