Re: [PATCH] telephony/ixj: Fix warning about sequence points

[Andrew Morton]

On Mon, 19 Mar 2012 11:57:44 +0100
Uwe Kleine-K__nig <uwe@xxxxxxxxxxxxxxxxx> wrote:

> In the statement
> 
> 	j->caplist[j->caps].handle = j->caps++;
> 
> there is no sequence point between the usage of j->caps on the LHS of the
> assignment and the incrementation on its RHS. So it's not defined in Standard C
> if j->caps is already incremented when used on the LHS even though the postfix
> ++ operator is used. To properly fix that the incrementation has to be done in
> a seperate expression.
> 
> This fixes:
> 	drivers/telephony/ixj.c: In function ___add_caps___:
> 	drivers/telephony/ixj.c:5930:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5950:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5954:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5965:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5976:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5988:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:5998:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6003:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6008:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6013:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6019:38: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6026:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6031:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6036:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6041:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6049:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6057:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6065:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 	drivers/telephony/ixj.c:6071:39: warning: operation on ___j->caps___ may be undefined [-Wsequence-point]
> 
> Signed-off-by: Uwe Kleine-K__nig <uwe@xxxxxxxxxxxxxxxxx>
> ---
>  drivers/telephony/ixj.c |   57 +++++++++++++++++++++++++++++++---------------

fyi, ixj.c has been moved into staging/, with a view to removing it
altogether.

It will be sad to see it go - it has stood as a great example of what not
to do ;)  And no, I don't now how to find out if anyone is using it either.
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