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authortilghman <tilghman@f38db490-d61c-443f-a65b-d21fe96a405b>2010-11-30 22:32:20 +0000
committertilghman <tilghman@f38db490-d61c-443f-a65b-d21fe96a405b>2010-11-30 22:32:20 +0000
commitc3e5b57e6c3940c03b0124149a9d7fa4153c48a8 (patch)
tree703847474b71d46512bb6578a0d61c225ea9de8d /include
parent5c39a3d77917c8a47e216f353e0726fedb8ba254 (diff)
Add a comment on why the reserved bit is reserved.
Came up when reviewing discussion on the CODEC PREFS IE in IAX2. git-svn-id: http://svn.digium.com/svn/asterisk/trunk@296826 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'include')
-rw-r--r--include/asterisk/frame.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/include/asterisk/frame.h b/include/asterisk/frame.h
index c16a3c150..b9eb75bd1 100644
--- a/include/asterisk/frame.h
+++ b/include/asterisk/frame.h
@@ -300,7 +300,13 @@ extern struct ast_frame ast_null_frame;
#define AST_FORMAT_SPEEX16 (1ULL << 33)
/*! Raw mu-law data (G.711) */
#define AST_FORMAT_TESTLAW (1ULL << 47)
-/*! Reserved bit - do not use */
+/*! Reserved bit - do not use
+ * \warning We use this bit internally for iteration. Additionally, using this
+ * bit will severely break the implementation of codec prefs within IAX2, as we
+ * rely on the equivalence of UTF-8 and ASCII. The codec represented by this
+ * bit should use the first two-byte encoding of UTF-8, which is not presently
+ * accounted for. Hence, we reserve this bit as unused.
+ */
#define AST_FORMAT_RESERVED (1ULL << 63)
enum ast_control_frame_type {