bytestring: Add initializer macro

The BYTESTRING macro is constant, since it's designed to take a string
literal, but it doesn't count as constant since it involves an (inlined)
function call.  That means it can't be used in a static storage duration
initializer.

Unfortunately, I can't see a portable way to make something which can be
used as an initializer, but which can also be used in other contexts where
BYTESTRING() can be used, so this patch introduces BYTESTRING_INIT() which
is similar to BYTESTRING() but produces an initializer.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

diff --git a/ccan/bytestring/bytestring.h b/ccan/bytestring/bytestring.h
index fd5187701b3430bd03f5cc60be080f0dfdc57b49..dd1f913ca45ee2f0dbe7d66f50f175256927095b 100644 (file)
--- a/ccan/bytestring/bytestring.h
+++ b/ccan/bytestring/bytestring.h
@@ -55,6 +55,18 @@ bytestring(const char *p, size_t l)
  */
 #define BYTESTRING(s) (bytestring((s), ARRAY_SIZE(s) - 1))
 
+/**
+ * BYTESTRING_INIT - bytestring initializer
+ * @s: string literal
+ *
+ * Produces an initializer for a bytestring from a literal string.
+ * The resulting bytestring will not include the terminating \0, but
+ * will include any internal \0s.
+ *
+ * Example:
+ *     static const struct bytestring CONSTANT = BYTESTRING_INIT("CONSTANT");
+ */
+#define BYTESTRING_INIT(s) { .ptr = (s), .len = ARRAY_SIZE(s) - 1}
 
 /**
  * bytestring_from_string - construct a bytestring from a NUL terminated string