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I am using the following code:

        'myplugin_options', //setting group name
        'myplugin_options', //option name that will be stored in the database
        'myplugin_validate_options'//optional callback function

function myplugin_validate_options($input) {
    //how can i print $input to the screen or view the output of this function for debugging purpsoses?


I just need to know how we can debug our validation callback functions. From what I see they can not be output to the screen so it makes writing correct code inside of them difficult.


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have you tried var_dump? – Bainternet Apr 13 '11 at 22:19
I do love me some var_dump. 90% of the time, it gives you everything you need, every time. – Drew Gourley Apr 14 '11 at 1:50
Yeah it looks like var_dump does the trick. I also noticed that print_r works too, but just a plain old echo does not output to the screen, strangely enough. – mike Apr 14 '11 at 13:06
That's probably because $input contains an array of data, you can't echo arrays. – t31os Apr 15 '11 at 10:45
You can echo arrays, it will just print Array... Even if you do echo 'hi'; it will not output. Give it a try. Debugging this function is a PIA. – mike Apr 15 '11 at 14:43

The dirty and only way I've founded:

function myplugin_validate_options($input) {

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When echoing ( echo($var) ) within 'library' code (ie. before the page is being built, as in the case here of register_setting) these statements will typically print just after the opening tag in the HTML but will often not show up there. I use PHP's built-in function error_log() to print whatever I want directly to PHP's error log. Then I can just open that file (usually php_error.log somewhere) and see the output. Work for you?

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none of the above solutions worked for me, I even tried the debug statements to a file.

A work around which does the job is

add a call to undefined function after all your debug statements, then the out put is printed to the screen.

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