[ovs-dev] [PATCH 4/4] uuid: New macro UUID_ZERO for an all-zero expression or initializer.

[Ben Pfaff]

This is convenient in expressions, e.g. "uuid = x ? *x : UUID_ZERO;".

Signed-off-by: Ben Pfaff <blp at ovn.org>
---
 lib/uuid.c | 2 +-
 lib/uuid.h | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/uuid.c b/lib/uuid.c
index bd98d40..a9094d3 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -115,7 +115,7 @@ uuid_set_bits_v4(struct uuid *uuid)
 void
 uuid_zero(struct uuid *uuid)
 {
-    uuid->parts[0] = uuid->parts[1] = uuid->parts[2] = uuid->parts[3] = 0;
+    *uuid = UUID_ZERO;
 }
 
 /* Returns true if 'uuid' is all zero, otherwise false. */
diff --git a/lib/uuid.h b/lib/uuid.h
index 113574c..605ec17 100644
--- a/lib/uuid.h
+++ b/lib/uuid.h
@@ -18,6 +18,9 @@
 
 #include "openvswitch/uuid.h"
 
+/* An initializer or expression for an all-zero UUID. */
+#define UUID_ZERO ((struct uuid) { .parts = { 0, 0, 0, 0 } })
+
 /* Formats a UUID as a string, in the conventional format.
  *
  * Example:
-- 
2.10.2