twentythirteen_paging_nav(); problem

What’s your style.css header look like?

/*
Theme Name:     Thème monthème (thirteen Child)
Theme URI:      https://example.com/
Description:    Thème Lisbeth de beauté
Author:         Votre nom ici
Author URI:     https://example.com/about/
Template:       twentythirteen
Version:        0.1.0
*/

@import url("../twentythirteen/style.css");

I don’t believe the error is there : all the other things i made in my theme child works.

That seems a little odd. I’m guessing you haven’t modified the twenty-thirteen theme, correct?

I haven’t…
It’s totally odd.

But warning: i have a functions.php in my child theme.
But nothing important i guess:

<?php
register_sidebar( array(
'name' => __( 'Footer Area One', 'twentyfourteen' ),
'id' => 'sidebar-4',
'description' => __( 'An optional widget area for your site footer', 'twentyfourteen' ),
'before_widget' => '<aside id="%1$s" class="widget %2$s">',
'after_widget' => "</aside>",
'before_title' => '<h3 class="widget-title">',
'after_title' => '</h3>',
) );

register_sidebar( array(
'name' => __( 'Footer Area Two', 'twentyfourteen' ),
'id' => 'sidebar-5',
'description' => __( 'An optional widget area for your site footer', 'twentyfourteen' ),
'before_widget' => '<aside id="%1$s" class="widget %2$s">',
'after_widget' => "</aside>",
'before_title' => '<h3 class="widget-title">',
'after_title' => '</h3>',
) );

register_sidebar( array(
'name' => __( 'Footer Area Three', 'twentyfourteen' ),
'id' => 'sidebar-6',
'description' => __( 'An optional widget area for your site footer', 'twentyfourteen' ),
'before_widget' => '<aside id="%1$s" class="widget %2$s">',
'after_widget' => "</aside>",
'before_title' => '<h3 class="widget-title">',
'after_title' => '</h3>',
) );
?>

<?php function custom_excerpt_length( $length ) {
	return 40;
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );
function new_excerpt_more( $more ) {
	return '<div class="fixclear"></div><a class="read-more" href="'. get_permalink( get_the_ID() ) . '">Read More</a>';
}
add_filter( 'excerpt_more', 'new_excerpt_more' );

?>

Do you get an error only when you are on a category page? When does the error occur?

When i have a category page or a single page:

fatal error: Call to undefined function twentythirteen_paging_nav() in C:\wamp\www\wordpress\wp-content\themes\mytheme\category.php

yeah strange.

Really strange. When I have some free time I’ll try and re-create this see if I can find some solution.

What happens if you switch back to the unedited parent theme?

@esmi: with the parent theme activated, all work fine!

I have also tried to re install the theme. But it’s the same.
onte thing strange too: when you’re in back office and you have your themes to choose, twenty thirteen have the title tewnty twelve… strange even if i have it reinstalled.

What happens if you just remove your child theme’s category.php template file?

it works.
But i must have category and single php in my theme child to change some things.

Well, at least this narrows the issue down to your category template file. Can you drop a copy of that file into a pastebin and post the pastebin url here so that we can have a look at it?

If u want but it’s just a copy from parent theme’s category.php
It’s juste the same file:

ici

If it’s exactly the same as the parent’s template file, why have you included it in the child theme? If you remove it, the child will automatically use the parent’s copy.