Problem with popen and rrdtool

[Roke]

Hi,

Im new on php but im having some problems with the popen function, i have this code:

if($fp = popen("/usr/bin/rrdtool fetch $_name AVERAGE",'r')){

trim(fgets($fp, 4096));
print $line;
while(!feof($fp)){
print $line;
$line = trim(fgets($fp, 4096));
}
}else print "ERROR";


I get not result and no error, i get a blank html but if i put

if($fp = popen("/usr/bin/rrdtool fetch /var/www/cacti/rra/1/32.rrd AVERAGE",'r')){

And i write the value of $_name i get results on the web. Why if i pass the value in a variable i get no result.

There is no error in the values, i think is format conversion. Maybe $_name is not totally a string and can give problem?

Best Regards.

[gandalf]

This is which version of cacti, please?
R.

[Roke]

Version 0.8.7g

I want to get the total bandwith in a period of time.

[Roke]

Now im using the function of cacti called bandwidth_summation

bandwidth_summation($local_data_id, $start_time, $end_time, $rra_steps, $ds_steps)

When i called for a period of 1 day with rra_steps =1 ds_steps=300 works great but when i put a bigger period, for example 7 days the results are wrong.

THe result of the function isnt the same of the graphic