Edit php files in subdirs in a child theme

Question

I want to change a php file in a subdir of my theme folder. The path to that specific file is:
/includes/sf-content-display/sf-post-formats.php

I copied the file within the subdirs in my child theme and made the changes.

It seems, if I read some articles, that I have to hook a selfmade function in a file functions.php in the child theme.

I did the folowing:

function require_once_child() {
    require_once('includes/sf-content-display/sf-post-formats.php');    
}

function require_once_child() {
    remove_action( 'init', 'require_once' );
    add_action( 'init', 'require_once_child' );
}
add_action( 'init', 'require_once_child' );

Result is an error:

Fatal error: Cannot redeclare require_once_child() (previously declared in /www/htdocs/keltenwo/wp/wp-content/themes/flexform-child/functions.php:3) in /www/htdocs/keltenwo/wp/wp-content/themes/flexform-child/functions.php on line 9

Any suggestions?

Answer 1

Any suggestions?

For one, read and interpret the error message.
"Cannot redeclare require_once_child()" is pretty straightforward: Don't give two functions the same name.

I am uncertain whether your general idea is sensible in the first place, but should it be, this

function require_once_child() {
    require_once('includes/sf-content-display/sf-post-formats.php');    
}
add_action( 'init', 'require_once_child' );

is all you need.