_doing_it_wrong( string $function_name, string $message, string $version )

function bookstore_get_price( $post_id, $legacy_currency = null ) {
	if ( null !== $legacy_currency ) {
		_doing_it_wrong(
			__FUNCTION__,
			'The $legacy_currency parameter is no longer used, prices are always stored in the site currency.',
			'7.1.0'
		);
	}

	return get_post_meta( $post_id, 'price', true );
}

// Capture the notice with a temporary error handler so it prints regardless of the WP_DEBUG setting.
set_error_handler( function( $errno, $errstr ) {
	echo '<p><strong>Triggered notice:</strong> ' . esc_html( wp_strip_all_tags( $errstr ) ) . '</p>';
	return true;
} );

$price = bookstore_get_price( 2, 'USD' );

restore_error_handler();

echo '<p>Price returned: ' . esc_html( $price ) . '</p>';
When	Instructions	Calls it makes
always	12	`do_action()`
`!apply_filters()`	20	`do_action(), apply_filters()`
`apply_filters() && !function_exists()`	37–41	`do_action(), apply_filters(), function_exists(), sprintf(), wp_trigger_error()`
`apply_filters() && function_exists()`	52	`do_action(), apply_filters(), function_exists(), __(), __(), sprintf(), __(), sprintf(), wp_trigger_error()`
`apply_filters() && function_exists()`	60	`do_action(), apply_filters(), function_exists(), __(), sprintf(), __(), __(), sprintf(), __(), sprintf(), wp_trigger_error()`
PHP	Compiled	Executed	Branches	Notes
8.6-dev	73	12–60	5
8.5	73	12–60	5
8.4	73	12–60	5	5 fewer instructions than PHP 8.3
8.3	78	12–60	5
8.2	78	12–60	5
8.1	78	12–60	5
7.4	78	12–60	5