From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <cyrus@holtmann.org>
Message-ID: <1326442873.6454.258.camel@aeonflux>
Subject: Re: [PATCH] Fix compilation of C++ programs that include
 <bluetooth/bluetooth.h>
From: Marcel Holtmann <marcel@holtmann.org>
To: Szymon Janc <szymon.janc@tieto.com>
Cc: linux-bluetooth@vger.kernel.org, kanak.gupta@stericsson.com
Date: Fri, 13 Jan 2012 09:21:13 +0100
In-Reply-To: <1326442733-11966-1-git-send-email-szymon.janc@tieto.com>
References: <1326442733-11966-1-git-send-email-szymon.janc@tieto.com>
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Sender: linux-bluetooth-owner@vger.kernel.org
List-ID: <linux-bluetooth.vger.kernel.org>

Hi Szymon,

> C++ doesn't allow for implicit conversion from void*.
> 
> /usr/include/bluetooth/bluetooth.h: In function ‘uint64_t bt_get_le64(void*)’:
> /usr/include/bluetooth/bluetooth.h:131: error: invalid conversion from ‘void*’ to ‘bt_get_le64(void*)::<anonymous struct>*’
> /usr/include/bluetooth/bluetooth.h: In function ‘uint64_t bt_get_be64(void*)’:
> /usr/include/bluetooth/bluetooth.h:136: error: invalid conversion from ‘void*’ to ‘bt_get_be64(void*)::<anonymous struct>*’
> /usr/include/bluetooth/bluetooth.h: In function ‘uint32_t bt_get_le32(void*)’:
> /usr/include/bluetooth/bluetooth.h:141: error: invalid conversion from ‘void*’ to ‘bt_get_le32(void*)::<anonymous struct>*’
> /usr/include/bluetooth/bluetooth.h: In function ‘uint32_t bt_get_be32(void*)’:
> /usr/include/bluetooth/bluetooth.h:146: error: invalid conversion from ‘void*’ to ‘bt_get_be32(void*)::<anonymous struct>*’
> /usr/include/bluetooth/bluetooth.h: In function ‘uint16_t bt_get_le16(void*)’:
> /usr/include/bluetooth/bluetooth.h:151: error: invalid conversion from ‘void*’ to ‘bt_get_le16(void*)::<anonymous struct>*’
> /usr/include/bluetooth/bluetooth.h: In function ‘uint16_t bt_get_be16(void*)’:
> /usr/include/bluetooth/bluetooth.h:156: error: invalid conversion from ‘void*’ to ‘bt_get_be16(void*)::<anonymous struct>*’
> ---
>  lib/bluetooth.h |   10 ++++++----
>  1 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/bluetooth.h b/lib/bluetooth.h
> index 5bd4f03..b4891ef 100644
> --- a/lib/bluetooth.h
> +++ b/lib/bluetooth.h
> @@ -111,17 +111,19 @@ enum {
>  /* Bluetooth unaligned access */
>  #define bt_get_unaligned(ptr)			\
>  ({						\
> -	struct __attribute__((packed)) {	\
> +	struct __s {				\
>  		typeof(*(ptr)) __v;		\
> -	} *__p = (void *) (ptr);		\
> +	} __attribute__((packed)) ;		\
> +	struct __s *__p = (struct __s *) (ptr);	\
>  	__p->__v;				\
>  })
>  
>  #define bt_put_unaligned(val, ptr)		\
>  do {						\
> -	struct __attribute__((packed)) {	\
> +	struct __s {				\
>  		typeof(*(ptr)) __v;		\
> -	} *__p = (void *) (ptr);		\
> +	}__attribute__((packed)) ;		\
> +	struct __s *__p = (struct __s *) (ptr);	\
>  	__p->__v = (val);			\
>  } while(0)
>  

you are messing with powers beyond your control here. I am not touching
this unless a GCC expert guarantees me that it equivalent.

Regards

Marcel