Re: [tpmdd-devel] [PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

From: Jason Gunthorpe
Date: Wed Oct 30 2013 - 12:45:43 EST


On Wed, Oct 30, 2013 at 01:40:27AM +0100, Peter Huewe wrote:
> strcmp does return the difference between two strings not only -1,0,1
> consequently
> if (strcmp (a,b) == -1)
> might lead to taking the wrong branch
>
> -> compare with <= instead.

I've always thought this was the preferred idiom:

cmp(a,b) == 0
cmp(a,b) < 0
cmp(a,b) > 0

As the operator matches what is actually happening in all cases.

'>= -1' doesn't mean a >= b.

Regards,
Jason
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