[Qemu-devel] [PATCH] slirp: Fix compiler warning for w64

[Qemu-devel] [PATCH] slirp: Fix compiler warning for w64

[Stefan Weil]

Casting a pointer to an integer value must use uintptr_t or intptr_t
(not long) for portable code. MinGW-w64 requires this because
sizeof(long) != sizeof(void *) for w64 hosts, so casting to long
raises a compiler warning.

I use uintptr_t instead of intptr_t because changing the sign does not
matter here and casting pointers to unsigned values seems more
reasonable (the unsigned value is a non negative offset.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 slirp/cksum.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/slirp/cksum.c b/slirp/cksum.c
index e43867d..6328660 100644
--- a/slirp/cksum.c
+++ b/slirp/cksum.c
@@ -75,7 +75,7 @@ int cksum(struct mbuf *m, int len)
 	/*
 	 * Force to even boundary.
 	 */
-	if ((1 & (long) w) && (mlen > 0)) {
+	if ((1 & (uintptr_t)w) && (mlen > 0)) {
 		REDUCE;
 		sum <<= 8;
 		s_util.c[0] = *(uint8_t *)w;
-- 
1.7.9

Re: [Qemu-devel] [PATCH] slirp: Fix compiler warning for w64

[Jan Kiszka]

On 2012-03-10 21:20, Stefan Weil wrote:
> Casting a pointer to an integer value must use uintptr_t or intptr_t
> (not long) for portable code. MinGW-w64 requires this because
> sizeof(long) != sizeof(void *) for w64 hosts, so casting to long
> raises a compiler warning.
> 
> I use uintptr_t instead of intptr_t because changing the sign does not
> matter here and casting pointers to unsigned values seems more
> reasonable (the unsigned value is a non negative offset.
> 
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> Signed-off-by: Stefan Weil <sw@weilnetz.de>
> ---
>  slirp/cksum.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/slirp/cksum.c b/slirp/cksum.c
> index e43867d..6328660 100644
> --- a/slirp/cksum.c
> +++ b/slirp/cksum.c
> @@ -75,7 +75,7 @@ int cksum(struct mbuf *m, int len)
>  	/*
>  	 * Force to even boundary.
>  	 */
> -	if ((1 & (long) w) && (mlen > 0)) {
> +	if ((1 & (uintptr_t)w) && (mlen > 0)) {
>  		REDUCE;
>  		sum <<= 8;
>  		s_util.c[0] = *(uint8_t *)w;

Thanks, I picked this up for the slirp queue for which I will send a
pull request later today.

Jan

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