wppaste
WordPress

twentysixteen_preview()

Since
Twenty Sixteen 1.0
Source
wp-content/themes/twentysixteen/inc/back-compat.php:80
Prevents the Theme Preview from being loaded on WordPress versions prior to 4.4.

Compatibility

WordPress
since Twenty Sixteen 1.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Performance profile

How much work a call to twentysixteen_preview() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
4–16

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 16.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

  • hookthird-party callbacksapply_filters()one call below twentysixteen_preview()

Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 2 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost twentysixteen_preview() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
!isset($value)4none
isset($value)16__(), sprintf(), wp_die()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev164–161
8.5164–161
8.4164–161
8.3164–161
8.2164–161
8.1164–1611 fewer instruction than PHP 7.4
7.4174–171

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 2

  • wp_die()Kills WordPress execution and displays HTML page with an error message.
  • __()Retrieves the translation of $text.

Source code

View on Trac View on GitHub 

function twentysixteen_preview() {	if ( isset( $_GET['preview'] ) ) {		wp_die(			sprintf(				/* translators: %s: The current WordPress version. */				__( 'Twenty Sixteen requires at least WordPress version 4.4. You are running version %s. Please upgrade and try again.', 'twentysixteen' ),				$GLOBALS['wp_version']			)		);	}}

Changelog

Introduced in Twenty Sixteen 1.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-content/themes/twentysixteen/inc/back-compat.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
Something wrong on this page? Report it and it gets fixed in the next regeneration.