测试RRD支持时PHP未捕获错误

Question

I have this PHP file which Im using to test RRD support:

<?php
$result=rrd_fetch( "/ang.rrd", array( "AVERAGE", "--resolution", "60", "--start", "-1d", "--end", "start+1h" ) );

foreach ( $result["data"]["myfield"] as $key => $value )
{
    echo "At timestamp $key, the value for myfield is $value.
";
}
?>

If I browse to the file I get the following:

PHP Fatal error:  Uncaught Error: Call to undefined function rrd_fetch() in /var/www/html/graph.php:2
Stack trace:
#0 {main}
  thrown in /var/www/html/graph.php on line 2

and if I try to run the file on the command line I get the following:

PHP Notice:  Undefined index: myfield in /var/www/html/graph.php on line 4
PHP Warning:  Invalid argument supplied for foreach() in /var/www/html/graph.php on line 4

Im not sure why. Could somebody shed some light on why this is happening please?

Answer 1

The answer lies in your error message:

Call to undefined function rrd_fetch

The issue is that the rrd functions are not provided by default. They have to be added by install the rrd pecl package.

Try installing rrd and retrying your code: https://pecl.php.net/package/rrd

rrd documentation: http://www.php.net/rrd