use Module::Load::Conditional qw[can_load];
# Are we running threads?
my $grThreaded = eval 'use threads; 1';
# If so, load thread modules
my ($grThreadModules) = {
    'threads::shared'   =>  undef,
    'Thread::Semaphore' =>  undef,
    };
if ( $grThreaded )
{
    unless ( can_load( modules => $grThreadModules ) )
    {
        print "ERROR: Cannot load threaded modules in $0. Exiting.";
        exit();
    }
}
use strict;

my($gnWarning);

if ( $grThreaded )
{
    # Does not work at all: Undefined subroutine &main::share
#    share($gnWarning);
    # This works in the debugger
    # However, if used in production:  
    #  Argument to share needs to be passed as ref
#    threads::shared::share($gnWarning);
    # This works at run time
    # However, if used under the debugger:
    # Type of arg 1 to threads::shared::share must be one of [$@%]
    #   (not single ref constructor)
    threads::shared::share(\$gnWarning);
}

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In the code, I found that just trying to declare a variable as shared fails as being an undefined subroutine.

If I give the full variable module/name, it will work, but if I try to use the Perl debugger, I have to use a reference to the variable.

So I'm stumped as to the behavior. I'm running perl 5.20.1 under Linux.

Thanks, Bill

In reply to Problem conditionally making variables shared if using threads by billgdev

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