Add nullability annotations

This allows clang to issue warnings at compile time when null is passed to a
non-null parameter.  For public entry points, also add assertions to catch such
issues when the compiler does not support this.

1 files changed, 11 insertions, 0 deletions

diff --git a/include/zix/attributes.h b/include/zix/attributes.h
index c8f77c4..255b315 100644
--- a/include/zix/attributes.h
+++ b/include/zix/attributes.h
@@ -74,6 +74,17 @@
 #  define ZIX_UNUSED(name) name
 #endif
 
+// Clang nullability annotations
+#if defined(__clang__) && __clang_major__ >= 7
+#  define ZIX_NONNULL _Nonnull
+#  define ZIX_NULLABLE _Nullable
+#  define ZIX_ALLOCATED _Null_unspecified
+#else
+#  define ZIX_NONNULL
+#  define ZIX_NULLABLE
+#  define ZIX_ALLOCATED
+#endif
+
 /**
    @}
 */