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Description

bool is_infinite ( float val )

Returns TRUE if val is infinite (positive or negative), like the result of log(0) or any value too big to fit into a float on this platform.

See also is_finite() and is_nan().

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is_infinite

stangelanda at arrowquick dot com
28-Aug-2007 07:29


Actually any string ending in INF is more appropriate than any string beginning with INF.  Since negative infinity evaluates to "-INF" but it is still infinite.  However in either case the STRING "INF" is not infinite, only a float that converts to "INF" or "-INF" is infinite.



A more appropriate function might be:

<?php

if (!is_defined('is_infinite')) { function is_infinite($val) {

    return (is_float($val) and ("$val"=='INF' or "$val"=='-INF'));

} }

?>

* However the above function is untested.

21-Aug-2006 08:54


@ david,



That will return true for any string ending with "INF".

I think substr("$value",0,3) would be more appropriate.

david(@t)nirvanis(d@t)org
31-Aug-2004 02:49


If you have PHP lower than 4.2 you can simulate the behaviour:



function is_infinite($value) {

   return (substr("$value",-3) == "INF");

}



(tested on php 4.1.2)

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