Re: [Qemu-devel] tests/Makefile.include non-portable use of $RANDOM

[Kamil Rytarowski <n54@gmx.com>]

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On 13.07.2017 19:32, Peter Maydell wrote:
> Currently our test makefile does
> 
>    MALLOC_PERTURB_=$${MALLOC_PERTURB_:-$$((RANDOM % 255 + 1))}
> 
> This works on bash, but $RANDOM is bash-specific.
> On dash, it doesn't do what we want, but it does do something:
> 
> $ echo $((RANDOM % 255 + 1))
> 1
> 
> On NetBSD the shell complains:
> # echo $((RANDOM % 255 + 1))
> -sh: arith: syntax error: "RANDOM % 255 + 1"
> 
> and so 'make check' doesn't work.
> 
> Any suggestions for something more portable?
> https://unix.stackexchange.com/questions/140750/generate-random-numbers-in-specific-range
> suggests
>   awk 'BEGIN{srand(); print int(1+rand()*256)}'
> and of course there are similar things possible with perl et al.
> 
> Or we could just have the makefile check whether we have bash,
> and if not then set
>   RANDOM=4
> 
> (thus putting NetBSD into the same boat as all our dash users).
> 
> Opinions?
> 

From the NetBSD point of view, please skip it. We support $RANDOM in
NetBSD 8.0_BETA.

> thanks
> -- PMM
> 



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