is_single

The timeline below displays how wordpress function is_single has changed across different WordPress versions. If a version is not listed, refer to the next available version below.

WordPress Version: 5.6

/**
 * Determines whether the query is for an existing single post.
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 * Conditional Tags} article in the Theme Developer Handbook.
 *
 * @since 1.5.0
 *
 * @see is_page()
 * @see is_singular()
 * @global WP_Query $wp_query WordPress Query object.
 *
 * @param int|string|int[]|string[] $post Optional. Post ID, title, slug, or array of such
 *                                        to check against. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 5.4

/**
 * Determines whether the query is for an existing single post.
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 * Conditional Tags} article in the Theme Developer Handbook.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query WordPress Query object.
 *
 * @param int|string|int[]|string[] $post Optional. Post ID, title, slug, or array of such
 *                                        to check against. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 5.3

/**
 * Determines whether the query is for an existing single post.
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 * Conditional Tags} article in the Theme Developer Handbook.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query WordPress Query object.
 *
 * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 5.1

/**
 * Determines whether the query is for an existing single post.
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 * Conditional Tags} article in the Theme Developer Handbook.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query Global WP_Query instance.
 *
 * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 5.0

/**
 * Determines whether the query is for an existing single post.
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 * 
 * For more information on this and similar theme functions, check out
 * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/ 
 * Conditional Tags} article in the Theme Developer Handbook.
 * 
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query Global WP_Query instance.
 *
 * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 4.6

/**
 * Is the query for an existing single post?
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query Global WP_Query instance.
 *
 * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1.0');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 4.4

/**
 * Is the query for an existing single post?
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query Global WP_Query instance.
 *
 * @param int|string|array $post Optional. Post ID, title, slug, or array of such. Default empty.
 * @return bool Whether the query is for an existing single post.
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 4.3

/**
 * Is the query for an existing single post?
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query
 *
 * @param mixed $post Post ID, title, slug, or array of such.
 * @return bool
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1');
        return false;
    }
    return $wp_query->is_single($post);
}

WordPress Version: 3.7

/**
 * Is the query for an existing single post?
 *
 * Works for any post type, except attachments and pages
 *
 * If the $post parameter is specified, this function will additionally
 * check if the query is for one of the Posts specified.
 *
 * @see is_page()
 * @see is_singular()
 *
 * @see WP_Query::is_single()
 * @since 1.5.0
 * @uses $wp_query
 *
 * @param mixed $post Post ID, title, slug, or array of such.
 * @return bool
 */
function is_single($post = '')
{
    global $wp_query;
    if (!isset($wp_query)) {
        _doing_it_wrong(__FUNCTION__, __('Conditional query tags do not work before the query is run. Before then, they always return false.'), '3.1');
        return false;
    }
    return $wp_query->is_single($post);
}