[Xen-changelog] [xen master] libxl: unconst the event argument to the event_occurs hook.

[patchbot@xxxxxxx]

commit 5fb11a07023959b6c91f7f37124699681011c03a
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Fri Apr 26 12:42:24 2013 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed May 1 13:00:57 2013 +0100

    libxl: unconst the event argument to the event_occurs hook.
    
    The event is supposed to become owned, and therefore freed, by the 
application
    and the const prevents this.
    
    Unfortunately there is no way to remove the const without breaking existing
    callers. The best we can do is use the LIBXL_API_VERSION provisions to 
remove
    the const for callers who wish only to support the 4.3 API and newer.
    
    Callers who wish to support 4.2 will need to live with casting away the 
const.
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Reviewed-by: Jim Fehlig <jfehlig@xxxxxxxx>
    Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 tools/libxl/libxl.h       |   14 ++++++++++++--
 tools/libxl/libxl_event.h |    6 +++++-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 25efa76..ef96bce 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -273,9 +273,9 @@
 #include <libxl_uuid.h>
 #include <_libxl_list.h>
 
-/* API compatibility. Only 0x040200 is supported at this time. */
+/* API compatibility. */
 #ifdef LIBXL_API_VERSION
-#if LIBXL_API_VERSION != 0x040200
+#if LIBXL_API_VERSION != 0x040200 && LIBXL_API_VERSION != 0x040300
 #error Unknown LIBXL_API_VERSION
 #endif
 #endif
@@ -308,6 +308,16 @@
  */
 #define LIBXL_HAVE_DEVICE_BACKEND_DOMNAME 1
 
+/*
+ * LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG
+ *
+ * This argument was erroneously "const" in the 4.2 release despite
+ * the requirement for the callback to free the event.
+ */
+#if LIBXL_API_VERSION != 0x040200
+#define LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG 1
+#endif
+
 /* Functions annotated with LIBXL_EXTERNAL_CALLERS_ONLY may not be
  * called from within libxl itself. Callers outside libxl, who
  * do not #include libxl_internal.h, are fine. */
diff --git a/tools/libxl/libxl_event.h b/tools/libxl/libxl_event.h
index 51f2721..27a65dc 100644
--- a/tools/libxl/libxl_event.h
+++ b/tools/libxl/libxl_event.h
@@ -64,7 +64,11 @@ void libxl_event_free(libxl_ctx *ctx, libxl_event *event);
 
 typedef struct libxl_event_hooks {
     uint64_t event_occurs_mask;
-    void (*event_occurs)(void *user, const libxl_event *event);
+    void (*event_occurs)(void *user,
+#ifndef LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG
+                         const
+#endif
+                         libxl_event *event);
     void (*disaster)(void *user, libxl_event_type type,
                      const char *msg, int errnoval);
 } libxl_event_hooks;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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