undefined function wp_tempnam()

wp_tempnam() is a valid WordPress function. Troubleshooting an issue like this has no easy answer and requires a much deeper look than we can provide as community volunteers, but as a guess, an error of this nature suggests that you are calling a WordPress function from outside of WordPress.

Also, I don't know what you mean by "I've implemented the PHP duplicate function." I am assuming you are referring to some sort of custom code or function, is that correct?

I suggest you enable WordPress debug to get a more detailed stack trace, or use a tool like Kint where you can see the results of what is being passed to wp_tempnam() just before it executes.

Thanks for your reply,

I implemented the duplication php code as shown here:

https://formidableforms.com/knowledgebase/php-examples/#kb-duplicate-an-entry

The full error from debug is:

Fatal error: Uncaught Error: Call to undefined function wp_tempnam() in /home/kuyazfjt/public_html/wp-content/plugins/formidable-pro/classes/models/FrmProFileField.php:896 Stack trace: #0 /home/kuyazfjt/public_html/wp-includes/class-wp-hook.php(286): FrmProFileField::duplicate_files_with_entry(1098, 140, Array) #1 /home/kuyazfjt/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array) #2 /home/kuyazfjt/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /home/kuyazfjt/public_html/wp-content/plugins/formidable/classes/models/FrmEntry.php(175): do_action('frm_after_dupli...', 1098, 140, Array) #4 /home/kuyazfjt/public_html/wp-content/plugins/formidable-pro/classes/models/FrmProEntry.php(245): FrmEntry::duplicate('460') #5 /home/kuyazfjt/public_html/wp-includes/class-wp-hook.php(286): FrmProEntry::duplicate_sub_entries(1075, 136, Array) #6 /home/kuyazfjt/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #7 /home/kuyazfjt/public_html/wp-includes/plug in /home/kuyazfjt/public_html/wp-content/plugins/formidable-pro/classes/models/FrmProFileField.php on line 896

I'm currently trying to figure this out but have opened a support ticket too

What version of Formidable Pro are you using? Line 896 in FrmProFileField.php is a blank line in the latest version (3.05). There's no code there. wp_tempnam() isn't called until line 898.

Make sure that the version numbers of Formidable and Formidable Pro are in sync.

I updated both Wordpress and Formidable Forms & Formidable Pro to the latest versions.
Fresh Wordpress install
Created a brand new form
Views
Pages
No 3rd party plugins

So i'm running everything on a "clean" setup.

I still get this error, very strange problem.

the wp_tempnam() function is defined in wp-admin/includes/file.php

I wonder if it's some kind of permissions problem. At this point i'm stuck for ideas really. It's a shame as duplicating entries is one of the core features of the form I need to build. For the time being i might simply disable file uploads until I find a solution to this.

If it helps anyone in the future this is how you solve the issue.

All you need to do is add this code immediately after line 881 (insert it in a new line on its own) of your formidable-pro/classes/models/FrmProFileField.php file:

include_once( ABSPATH . 'wp-admin/includes/file.php' );