On Thu, Dec 15, 2011 at 10:09 AM, shawn wilson <ag4ve...@gmail.com> wrote:
> Strace stat(64) should do you.
> On Dec 15, 2011 8:03 AM, "Ken Peng" <short...@gmail.com> wrote:
>
> > Hello,
> >
> > Which module could show the order of loading modules?
> > For example,
> >
> > use Foo;
> > use Bar;
> >
> > BEGIN {
> > require A;
> > }
> >
> > I want to know in what order Perl loads these modules.
> >
> > Thanks.
> >
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> > http://learn.perl.org/
> >
> >
> >
>
The order is Foo, Bar, A; Figuring it out without a module is pretty simple
if you know that use is actually roughly the same as saying
BEGIN {
require Foo; Foo->import();
}
And you know from reading the documentation (perlmod, I think) that BEGIN
blocks are run in FIFO order -- So the first one seen is run fist, then the
second, and so on.
But, assuming that you have a truly preposterous amount of modules loading
from everywhere and can't check manually, you can actually ask Perl to tell
you. There's probably a module on CPAN for this, so this is superfluous,
but it's a nice enough exercise.
There's two options. An @INC hook, or overriding *CORE::GLOBAL::require.
Both have horrible caveats, so this is not something you should use in
production unless you know very well what you are doing.
The latter is pretty simple:
BEGIN { *CORE::GLOBAL::require = sub { say "[@_]"; CORE::require(@_) } }
And while that will tell you the order alright, it'll break pretty soon if
one of your modules rather rightfully also asks for a minimum version
number, like:
use List::Util v1;
The second way is using an @INC hook, which is explained in perldoc -f
require. Here's a pretty simple form:
BEGIN { unshift @INC, sub { say "@_[0..$#_]"; return } }
But the real question here is, why do you need to know this?
