[Mesa-dev] [PATCH 1/5] mesa: add STATIC_ASSERT() macro for compile-time assertions

[Brian Paul]

This can be used to check that tables have the right number of entries,
etc. at compile-time.  This will hopefully catch things that are missed
if particular drivers aren't tested, for example.
---
 src/mesa/main/compiler.h |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/src/mesa/main/compiler.h b/src/mesa/main/compiler.h
index 921e302..96e24e4 100644
--- a/src/mesa/main/compiler.h
+++ b/src/mesa/main/compiler.h
@@ -310,6 +310,17 @@ static INLINE GLuint CPU_TO_LE32(GLuint x)
 #endif
 #endif
 
+
+/**
+ * Static (compile-time) assertion.
+ * Basically, use COND to dimension an array.  If COND is false/zero the
+ * array size will be -1 and we'll get a compilation error.
+ */
+#define JOIN(x, y) x##y
+#define STATIC_ASSERT_LINE(COND, LINE) do { typedef int JOIN(static_assertion_failed_at_line_,LINE)[(!!(COND))*2-1]; } while (0)
+#define STATIC_ASSERT(COND)  STATIC_ASSERT_LINE(COND, __LINE__)
+
+
 #if (__GNUC__ >= 3)
 #define PRINTFLIKE(f, a) __attribute__ ((format(__printf__, f, a)))
 #else
-- 
1.7.3.4