Re: Prototype Mismatch in ModPerl::PerlRun

Was wrong on one of my statements: use Digest::SHA qw(sha256) _does_ 
produce the warning, after all. And with use Time::HiRes qw(usleep 
tv_interval) usleep produces the warning, but tv_interval does not. 
tv_interval is directly defined in Time::HiRes, the rest is C code. 
Maybe only XS loaded code triggers the warnings?

Cheers!

Dan

On 5/18/2021 3:26 PM, Daniel Ragle wrote:
> Ed, thanks for your response!
> 
> I had already tried most of your suggestions: Putting the module load in 
> the startup (with or without the import) didn't make a difference (still 
> get the prototype mismatch on the second and subsequent runs of the 
> script); and yah, importing nothing and referring to the sub directly 
> via Time::HiRes::time() makes the error go away (presumably because 
> nothing is imported).
> 
> I had originally thought it would warn on any import, but after reading 
> your message I did a little more experimenting. It's true that not all 
> modules/routines will trigger the warning; as a test I just tried use 
> Digest::SHA qw(sha256) and it did not trigger the warning. However it 
> looks like it does happen for more than just overwritten CORE routines. 
> For example I can trigger the warning with use JSON qw(to_json); and use 
> Fcntl qw(:flock) generates the warning separately for each symbol imported.
> 
> Prototype mismatch: sub 
> ModPerl::ROOT::ModPerl::PerlRunPrefork::var_www_test_test5_2epl::LOCK_SH: none 
> vs () at /var/www/test/test5.pl line 8.
> Prototype mismatch: sub 
> ModPerl::ROOT::ModPerl::PerlRunPrefork::var_www_test_test5_2epl::LOCK_NB: none 
> vs () at /var/www/test/test5.pl line 8.
> Prototype mismatch: sub 
> ModPerl::ROOT::ModPerl::PerlRunPrefork::var_www_test_test5_2epl::LOCK_UN: none 
> vs () at /var/www/test/test5.pl line 8.
> Prototype mismatch: sub 
> ModPerl::ROOT::ModPerl::PerlRunPrefork::var_www_test_test5_2epl::LOCK_EX: none 
> vs () at /var/www/test/test5.pl line 8.
> 
> Cheers!
> 
> Dan
> 
> On 5/14/2021 5:23 PM, Edward J. Sabol wrote:
>> Hi, Daniel. This error can happen even under regular Perl in some 
>> circumstances when a package redefines a core function ((like what 
>> importing Time::HiRes does here with time).
>>
>> I would change "use Time::HiRes qw(time);" to "use Time::HiRes ();" 
>> and then change "time()" on line 13 to "Time::HiRes::time()." Does 
>> that make the message go away?
>>
>> Even better would be to move or add "use Time::HiRes ();" to your 
>> startup.pl. I think it's generally a good idea (I want to say "best 
>> practice" even) to not import any functions or variables in your 
>> startup.pl, so I always add " ()" to my "use" statements there. You 
>> can then *usually* import specific functions with "use Whatever 
>> qw(func);" in your scripts. The problem here though is that the import 
>> is redefining the core function, and I think that can just be 
>> problematic.
>>
>> I think the moral here is that ModPerl::PerlRun* is not a perfect 
>> drop-in replacement for a Perl CGI. With mod_perl, there's usually 
>> something you need to tweak (like how global variables and things like 
>> that) slightly in order to get it working as intended, but the changes 
>> are usually minor and make sense once you wrap your head around how 
>> mod_perl works.
>>
>> Hope this helps!
>>
>> Regards,
>> Ed
>>
>> On May 14, 2021, at 9:36 AM, Daniel Ragle <[email protected]> wrote:
>>> I'm investigating short term solutions for site performance (long 
>>> term is a full rewrite of the app) and I'm working for the first time 
>>> with ModPerl::PerlRun (and ModPerl::PerlRunPrefork, both seem to 
>>> exhibit the same behavior) and feel like I'm missing something obvious.
>>>
>>> I have this reduction (as test2.pl):
>>>
>>> ####################
>>> #!/usr/bin/perl
>>>
>>> use strict;
>>> use warnings;
>>>
>>> use Time::HiRes qw(time);
>>>
>>> use CGI;
>>> my $cgi = CGI->new();
>>>
>>> print $cgi->header();
>>> print "<h1>Hello World</h1>\n";
>>> print "<h1>HiRes time is: ", time(), "</h1>\n";
>>> #####################
>>>
>>> The script runs properly as far as I can see, but I'm getting 
>>> Prototype Mismatch warnings in the log with each hit after the first 
>>> one:
>>>
>>> Prototype mismatch: sub 
>>> ModPerl::ROOT::ModPerl::PerlRunPrefork::var_www_test_test2_2epl::time: none 
>>> vs () at /var/www/test/test2.pl line 6.
>>
>>