use IO::Select;
my $sock_read_hdl = IO::Select->new();
$sock_read_hdl->add($oSocket);

# Block here until message arrives
my ($read_ready) = IO::Select->select($sock_read_hdl, undef, undef, undef);

# Now we are ready to read message. Note: $read_ready->[0] == $oSocket here.
eval { ... } or die $@; # As pointed out by ikegami, thanks.