Re: pl/perl extension fails on Windows

On Thu, Aug 10, 2017 at 8:06 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Thu, Aug 10, 2017 at 8:30 AM, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
>>> So, the question is should we allow the preprocessor option
>>> '_USE_32BIT_TIME_T' to be defined implicitly or not in postgresql
>>> provided we are using Visual C compiler version > 8.0. I think this
>>> should make plperl compatible with perl binaries.
>
>> We've got this code in MSBuildProject.pm and VCBuildProject.pm:
>
>> # We have to use this flag on 32 bit targets because the 32bit perls
>> # are built with it and sometimes crash if we don't.
>> my $use_32bit_time_t =
>> $self->{platform} eq 'Win32' ? '_USE_32BIT_TIME_T;' : '';
>
>> Based on the discussion upthread, I think we now know that this was
>> not really the right approach.
>
> Yeah ... however, if that's there, then there's something wrong with
> Ashutosh's explanation, because that means we *are* building with
> _USE_32BIT_TIME_T in 32-bit builds. It's just getting there in a
> roundabout way. (Or, alternatively, this code is somehow not doing
> anything at all.)

I am extremely sorry if i have communicated the things wrongly, what i
meant was we are always considering _USE_32BIT_TIME_T flag to build
plperl module on Windows 32-bit platform but unfortunately that is not
being considered/defined in perl code in case we use VC++ compiler
version greater than 8.0. and that's the reason for the binary
mismatch error on 32 bit platform.

Here, is what has been mentioned in 'win32/GNUMakefile' in perl source
for version 5.24.1

# In VS 2005 (VC++ 8.0) Microsoft changes time_t from 32-bit to
# 64-bit, even in 32-bit mode. It also provides the _USE_32BIT_TIME_T
# preprocessor option to revert back to the old functionality for
# backward compatibility. We define this symbol here for older 32-bit
# compilers only (which aren't using it at all) for the sole purpose
# of getting it into $Config{ccflags}. That way if someone builds
# Perl itself with e.g. VC6 but later installs an XS module using VC8
# the time_t types will still be compatible.
ifeq ($(WIN64),undef)
ifeq ((PREMSVC80),define)
BUILDOPT += -D_USE_32BIT_TIME_T
endif
endif

>
>> The trouble with that is that _USE_32BIT_TIME_T also affects how
>> PostgreSQL code compiles.
>
> Really? We try to avoid touching "time_t" at all in most of the code.
> I bet that we could drop the above-cited code, and compile only plperl
> with _USE_32BIT_TIME_T, taken (if present) from the Perl flags, and
> it'd be fine. At least, that's my first instinct for what to try.
>