From 21c794102c27d8474809cb54578941f8bbe63218 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>

Date: Tue, 28 Feb 2012 11:22:11 +0100

Subject: [PATCH] Fix compiling C++ applications

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The compiler error is:

 /usr/include/bluetooth/bluetooth.h::131:9: error: invalid conversion from 'void*' to 'bt_get_le64(void*)::<anonymous struct>*'

 ...

The reason is that C++, in contrast to C, does not allow conversion of

void * to anything, and this code gets compiled as C++ when the app is

written in C++. The macro with the assignment itself is older, but only

recent Bluez starts to use it in inline functions, thus triggering the

problem.

This patch keeps the "struct __attribute__((packed))" magic and merely

changes the typecast so that it works in C and C++. Like the existing

macro this patch relies on support for typeof.

The new variant of the code is in an ifdef and only used for C++

to avoid unexpected regressions in C applications.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>

---

 lib/bluetooth.h |   31 +++++++++++++++++++++++++++++++

 1 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/lib/bluetooth.h b/lib/bluetooth.h

index 5bd4f03..3f1a177 100644

--- a/lib/bluetooth.h

+++ b/lib/bluetooth.h

@@ -109,6 +109,12 @@ enum {

 #endif

 /* Bluetooth unaligned access */

+#ifndef __cplusplus

+/*

+ * traditional code, doesn't work in C++ because

+ * of the void * to struct pointer assignment

+ */

+

 #define bt_get_unaligned(ptr)			\

 ({						\

 	struct __attribute__((packed)) {	\

@@ -125,6 +131,31 @@ do {						\

 	__p->__v = (val);			\

 } while(0)

+#else /* __cplusplus */

+

+/*

+ * modified code with typeof typecast, for C++;

+ * the traditional code continues to be used for

+ * C to avoid unexpected regressions with this

+ * code here (it should work in C and C++, though)

+ */

+#define bt_get_unaligned(ptr)                  \

+({                                             \

+       struct __attribute__((packed)) {        \

+               typeof(*(ptr)) __v;             \

+       } *__p = (typeof(__p)) (ptr);           \

+       __p->__v;                               \

+})

+

+#define bt_put_unaligned(val, ptr)             \

+do {                                           \

+       struct __attribute__((packed)) {        \

+               typeof(*(ptr)) __v;             \

+       } *__p = (typeof(__p)) (ptr);           \

+       __p->__v = (val);                       \

+} while(0)

+#endif /* __cplusplus */

+

 #if __BYTE_ORDER == __LITTLE_ENDIAN

 static inline uint64_t bt_get_le64(void *ptr)

 {

-- 

1.7.7.6