use strict;

my $diafile="RT_4.dia";
open(FDIA, $diafile) or die "cannot open $diafile";

my @s = stat($diafile);
print "Dateigroesse ",$s[7]," Bytes\n";

my $rec;
my $totlen=0;
my $template = "d";
my $len = length pack($template,0.);
while (1) {
    my $res=read(FDIA,$rec,$len);
    if (!defined($res)) {print $totlen," error"; last;};
    if ($res==0) {print "OK\n"; last;};
    if ($res<$len) {print $res,"<",$len,"  length_read=",$totlen+$res; last;};
    $totlen+=$len;
}