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Date: Tue, 18 Jun 2013 12:13:38 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH V2] build: remove compile warning
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To: Markus Armbruster <armbru@redhat.com>
Cc: peter.maydell@linaro.org, aliguori@us.ibm.com, qemu-devel@nongnu.org, Robert Relyea <rrelyea@redhat.com>, alevy@redhat.com, stefanha@redhat.com, mlureau@redhat.com, Wenchao Xia <xiawenc@linux.vnet.ibm.com>

Il 07/06/2013 14:17, Markus Armbruster ha scritto:
>> diff --git a/util/iov.c b/util/iov.c
>> index cc6e837..b91cfb9 100644
>> --- a/util/iov.c
>> +++ b/util/iov.c
>> @@ -146,7 +146,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
>>  {
>>      ssize_t total = 0;
>>      ssize_t ret;
>> -    size_t orig_len, tail;
>> +    size_t orig_len = 0, tail;
>>      unsigned niov;
>>  
>>      while (bytes > 0) {
> 
> Here are the uses of orig_len:
> 
>         if (tail) {
>             /* second, fixup the last element, and remember the original
>              * length */
>             assert(niov < iov_cnt);
>             assert(iov[niov].iov_len > tail);
>             orig_len = iov[niov].iov_len;
>             iov[niov++].iov_len = tail;
>         }
> 
>         ret = do_send_recv(sockfd, iov, niov, do_send);
> 
>         /* Undo the changes above before checking for errors */
>         if (tail) {
>             iov[niov-1].iov_len = orig_len;
>         }
> 
> 
> gcc is too stupid to understand the control flow.  The initialization
> shuts it up.

Looks like most people's GCC is not that stupid, or I would have broken
build for everyone, right?

Paolo