_canonical_charset( string $charset ): string
- Since
- 3.6.0
- Source
wp-includes/functions.php:7731
Compatibility
- WordPress
- since 3.6.0
- 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.
Parameters
$charsetstring- A charset name, e.g. "UTF-8", "Windows-1252", "SJIS".
Return value
string- The canonical form of the charset.
Performance profile
How much work a call to _canonical_charset() 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
- Moderate
- Scaling
- Constant
- Instructions
- 6–18
- Plugin surface
- None
- Called by
- 2
Reads stored settings via get_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 20.
Nothing here hands control to plugin code.
2 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- optionoption read or write
get_option()one call below _canonical_charset()
Further down the call graph this can also reach hook, cache, serialize, query 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 · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost _canonical_charset() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
is_utf8_charset() | 6 | is_utf8_charset() |
!is_utf8_charset() | 12 | is_utf8_charset(), strcasecmp() |
!is_utf8_charset() | 18 | is_utf8_charset(), strcasecmp(), strcasecmp() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 20 instructions, 6–18 executed per call, 3 branches. The work does not change between versions.
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 · 1
- is_utf8_charset()Indicates if a given slug for a character set represents the UTF-8 text encoding. If not provided, examines the current blog's charset.
Used by · 2
- _wp_die_process_input()Processes arguments passed to wp_die() consistently for its handlers.
- _wp_specialchars()Converts a number of special characters into their HTML entities.
Source code
function _canonical_charset( $charset ) { if ( is_utf8_charset( $charset ) ) { return 'UTF-8'; } /* * Normalize the ISO-8859-1 family of languages. * * This is not required for htmlspecialchars(), as it properly recognizes all of * the input character sets that here are transformed into "ISO-8859-1". * * @todo Should this entire check be removed since it's not required for the stated purpose? * @todo Should WordPress transform other potential charset equivalents, such as "latin1"? */ if ( ( 0 === strcasecmp( 'iso-8859-1', $charset ) ) || ( 0 === strcasecmp( 'iso8859-1', $charset ) ) ) { return 'ISO-8859-1'; } return $charset;}Changelog
Introduced in 3.6.0. Unchanged from 6.7.7 through 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-includes/functions.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.