The delayed loading happens as you show, but even after the delayed load, the now-defined function still lacks a prototype: 

use POSIX qw( CHAR_MAX );
BEGIN { my $x= CHAR_MAX(); }
BEGIN { print defined(\&CHAR_MAX), $/; }
for(qw( CHAR_MAX POSIX::CHAR_MAX )) {
    my $proto= prototype($_);
    $proto= "..."   if  ! defined $proto;
    print "$_($proto)\n";
}
print CHAR_MAX, $/;
print CHAR_MAX+1, $/;
__END__
Produces:
1
CHAR_MAX(...)
POSIX::CHAR_MAX(...)
127
127

[download]

- tye        

In reply to Re^2: Beware of POSIX constants (sorta) by tye
in thread Beware of POSIX constants by tlm

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.