Exclude categories from single post pagination

gistfile1.txt

if ( ! function_exists( 'generate_content_nav' ) ) {
	/**
	 * Display navigation to next/previous pages when applicable.
	 *
	 * @since 0.1
	 *
	 * @param string $nav_id The id of our navigation.
	 */
	function generate_content_nav( $nav_id ) {
		if ( ! apply_filters( 'generate_show_post_navigation', true ) ) {
			return;
		}

		global $wp_query, $post;

		// Don't print empty markup on single pages if there's nowhere to navigate.
		if ( is_single() ) {
			$previous = ( is_attachment() ) ? get_post( $post->post_parent ) : get_adjacent_post( false, '', true );
			$next = get_adjacent_post( false, '', false );

			if ( ! $next && ! $previous ) {
				return;
			}
		}

		// Don't print empty markup in archives if there's only one page.
		if ( $wp_query->max_num_pages < 2 && ( is_home() || is_archive() || is_search() ) ) {
			return;
		}

		$nav_class = ( is_single() ) ? 'post-navigation' : 'paging-navigation';
		$category_specific = apply_filters( 'generate_category_post_navigation', false );
		?>
		<nav id="<?php echo esc_attr( $nav_id ); ?>" class="<?php echo esc_attr( $nav_class ); ?>">
			<span class="screen-reader-text"><?php esc_html_e( 'Post navigation', 'generatepress' ); ?></span>

			<?php if ( is_single() ) : // navigation links for single posts.

				previous_post_link(
					'<div class="nav-previous"><span class="prev" title="' . esc_attr__( 'Previous', 'generatepress' ) . '">%link</span></div>',
					'%title',
					$category_specific,
					array( '3453' )
				);

				next_post_link(
					'<div class="nav-next"><span class="next" title="' . esc_attr__( 'Next', 'generatepress' ) . '">%link</span></div>',
					'%title',
					$category_specific,
					array( '3453' )
				);

			elseif ( is_home() || is_archive() || is_search() ) : // navigation links for home, archive, and search pages.

				if ( get_next_posts_link() ) : ?>
					<div class="nav-previous"><span class="prev" title="<?php esc_attr_e( 'Previous', 'generatepress' );?>"><?php next_posts_link( __( 'Older posts', 'generatepress' ) ); ?></span></div>
				<?php endif;

				if ( get_previous_posts_link() ) : ?>
					<div class="nav-next"><span class="next" title="<?php esc_attr_e( 'Next', 'generatepress' );?>"><?php previous_posts_link( __( 'Newer posts', 'generatepress' ) ); ?></span></div>
				<?php endif;

				if ( function_exists( 'the_posts_pagination' ) ) {
					the_posts_pagination( array(
						'mid_size' => apply_filters( 'generate_pagination_mid_size', 1 ),
						'prev_text' => apply_filters( 'generate_previous_link_text', __( '&larr; Previous', 'generatepress' ) ),
						'next_text' => apply_filters( 'generate_next_link_text', __( 'Next &rarr;', 'generatepress' ) ),
					) );
				}

				/**
				 * generate_paging_navigation hook.
				 *
				 * @since 0.1
				 */
				do_action( 'generate_paging_navigation' );

			endif; ?>
		</nav><!-- #<?php echo esc_html( $nav_id ); ?> -->
		<?php
	}
}