从fdf_get_value（）获取错误

I was trying to get field value from fdf file. I have used following code, but getting error.

<?php
$fdf = fdf_open("test1.fdf");
echo "Name: ",fdf_get_value($fdf,"first_name");
fdf_close($fdf);
?>

Error message:

Fatal error: Call to undefined function fdf_get_value() in C:\LocalServer\htdocs\pdf\test.php on line 3

Do I have to install any library function? I do not know what I should do.

Yes, you need to have the library installed - see http://www.php.net/manual/en/fdf.requirements.php