I used the below quick program to access gmail account via IMAP. The module I use is Net::IMAP::Simple and it's docs tell us that the search in IMAP is defined in RFC 5256. The module has the capability to search but a a quick (read: no exhaustive) serach seems to suggest that gmail doesn't support RFC 5256. Anyway I confirm that the only search that runs ok with gmail is $imap->search("ALL")

use strict;
use warnings;

# required modules
use Net::IMAP::Simple;
use Email::Simple;
use IO::Socket::SSL;
use HTML::Strip;
use Data::Dump;

# fill in your details here
my $username = 'my_account_of_gmail@gmail.com';
my $password = $ARGV[0] || die "password as first argument!";
my $mailhost = 'pop.gmail.com';

# Connect
my $imap = Net::IMAP::Simple->new(
    $mailhost,
    port    => 993,
    use_ssl => 1,
) || die "Unable to connect to IMAP: $Net::IMAP::Simple::errstr\n";

my $hs = HTML::Strip->new();

# Log in
if ( !$imap->login( $username, $password ) ) {
    print STDERR "Login failed: " . $imap->errstr . "\n";
    exit(64);
}
# Look in the the INBOX
my $nm = $imap->select('INBOX');

# How many messages are there?
my ($unseen, $recent, $num_messages) = $imap->status();
print "unseen: $unseen, recent: $recent, total: $num_messages\n\n";


## Iterate through unseen messages
for ( my $i = 1 ; $i <= $nm ; $i++ ) {
    #last if $i == 2;
    if ( $imap->seen($i) ) {
        next;
    }
    else {
    my $es = Email::Simple->new( join '', @{ $imap->get($i) } );


    printf( "[%03d] %s\n", $i, $es->header('From'), $es->header('Subje
+ct'));
    #print "BODY[".$es->body."]\n\n";
    print "Cc-------------->", $es->header('Cc'),"\nTo------>",$es->he
+ader('To'),"\n";
    #dd $es;
    print $hs->parse( $es->body );
    print +('=' x 70),"\n";
    }
}
# Disconnect
$imap->quit;

exit;
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