Re: [Qemu-devel] [PATCH 2/4] Add cleanup function

[Eric Blake <eblake@redhat.com>]

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On 01/16/2012 10:16 AM, Ryan Harper wrote:
>>>  if test -z "$1" -o -z "$2"; then
>>>      echo "Usage: $0 QEMU TEST1 [TEST2 ...]"
>>> +    cleanup
>>>      exit 1
>>
>> Is it worth using 'trap cleanup 0' to install the cleanup handler up
>> front, instead of modifying all exit call sites?
> 
> I thought about that, but it seemed to require switching to /bin/bash

Not really.

> 
> and I know Anthony had written the scripts carefully to be /bin/sh.

POSIX requires /bin/sh to support 'trap cleanup 0', and I don't know of
any counter-example shells that fail to do this.  There are non-POSIX
shells where installing a trap 0 handler from inside a function body
invokes the handler upon exiting the function, instead of exiting the
overall script, but even Solaris /bin/sh knows how to correctly handle a
trap 0 handler installed outside of any function calls.

https://www.gnu.org/software/autoconf/manual/autoconf.html#trap

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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