Perl DBI sets $SIG{PIPE} to 'IGNORE'

>
> I'm using MySQL, any idea where I should report the problem to?
>
> (I'm a biologist not a computer programmer, apologies for my  
> ignorance)
>
> thanks
>
> Damian
>
>
> On 28 Jul 2010, at 19:22, Martin J. Evans wrote:
>
>> Damian Keefe wrote:
>>> Hi Folks
>>>
>>> $DBI::VERSION = "1.609"
>>> perl, v5.8.8 built for x86_64-linux-thread-multi
>>> SHELL=/bin/tcsh
>>>
>>> I'm not sure if this should be considered a bug in DBI or  
>>> elsewhere, but it has unpleasant consequences. Somewhere in the  
>>> bowels of DBI, SIGPIPE gets set to 'IGNORE'. It remains in this  
>>> state after disconnect(). If you then launch a second script  
>>> using backticks and this script contains a line like
>>>
>>> my $first_line = `grep -v '#' $filename|head -n 1`; # to get the  
>>> first non-comment line
>>>
>>> the shell which is invoked inherits the SIGPIPE = 'IGNORE' state.  
>>> This causes a
>>> grep: writing output: Broken pipe
>>> error as the grep tries to write to the head process which has  
>>> exited.
>>>
>>> It took me a while to work this out because of the way perl  
>>> populates the %SIG hash. It appears it only populates it once  
>>> from the system when it is first used in the script. If you run  
>>> the script below with the first print statement commented out you  
>>> get
>>>
>>> connected to dk_funcgen_classify_59_MEF
>>> SIGPIPE=IGNORE
>>>
>>> If you uncomment the first print statement you get
>>>
>>> SIGPIPE=UNDEF
>>> connected to dk_funcgen_classify_59_MEF
>>> SIGPIPE=UNDEF
>>>
>>> However, behind the scenes, something has changed SIGPIPE to  
>>> IGNORE and the %SIG hash has not been updated.
>>>
>>> (my workaround is to explicitly reset SIGPIPE to 'DEFAULT' in the  
>>> second script)
>>>
>>> cheers
>>>
>>> Damian
>>>
>>>
>> I suspect you'll find its your driver library that ignores SIGPIPE  
>> as AFAIK, DBI does not.
>> Oracle's OCI library changes some signal dispositions for sure and  
>> sometimes SIGPIPE/SIGCHLD.
>>
>> Martin
>>
>> <snipped example code>
>