commit 51e430392d125ad7b36ec43e1448f3235d221b39
author Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at> Fri Dec 02 01:09:23 2016
committer Stefan Tauner <stefan.tauner@gmx.at> Thu Oct 12 01:50:05 2017
tree be44c2f0cc049d5c822acd9bce422f35b8a94339
parent 9fbbf55ecb991704cfbb2900ad9b41a1f7647759

Fix undefined behavior in some preprocessor define checks

Macros like the one below would produce undefined behavior when used as
expression/condition in #if preprocessor directives:
This patch replaces all such statements with a more verbose but
well-defined #if/#define x 1/#else/#define x 0/#endif

Found by clang (warning introduced in r258128), reported by Idwer.

Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>

hwaccess.c

diff --git a/hwaccess.c b/hwaccess.c
index 1901ee6..80852e7 100644
--- a/hwaccess.c
+++ b/hwaccess.c
@@ -37,9 +37,21 @@
 #error "Unknown operating system"
 #endif
 
-#define USE_IOPL	(IS_LINUX || IS_MACOSX || defined(__NetBSD__) || defined(__OpenBSD__))
-#define USE_DEV_IO	(defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__))
-#define USE_IOPERM	(defined(__gnu_hurd__))
+#if (IS_LINUX || IS_MACOSX || defined(__NetBSD__) || defined(__OpenBSD__))
+	#define USE_IOPL (1)
+#else
+	#define USE_IOPL (0)
+#endif
+#if (defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__))
+	#define USE_DEV_IO (1)
+#else
+	#define USE_DEV_IO (0)
+#endif
+#if (defined(__gnu_hurd__))
+	#define USE_IOPERM (1)
+#else
+	#define USE_IOPERM (0)
+#endif
 
 #if USE_IOPERM
 #include <sys/io.h>

platform.h

diff --git a/platform.h b/platform.h
index c5a52ef..d70a6e0 100644
--- a/platform.h
+++ b/platform.h
@@ -25,9 +25,21 @@
 #define __PLATFORM_H__ 1
 
 // Helper defines for operating systems
-#define IS_LINUX	(defined(__gnu_linux__) || defined(__linux__))
-#define IS_MACOSX	(defined(__APPLE__) && defined(__MACH__)) /* yes, both. */
-#define IS_WINDOWS	(defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(__WINDOWS__))
+#if (defined(__gnu_linux__) || defined(__linux__))
+	#define IS_LINUX (1)
+#else
+	#define IS_LINUX (0)
+#endif
+#if (defined(__APPLE__) && defined(__MACH__)) /* yes, both. */
+	#define IS_MACOSX (1)
+#else
+	#define IS_MACOSX (0)
+#endif
+#if (defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(__WINDOWS__))
+	#define IS_WINDOWS (1)
+#else
+	#define IS_WINDOWS (0)
+#endif
 
 // Likewise for target architectures
 #if defined (__i386__) || defined (__x86_64__) || defined(__amd64__)