IntlChar getCombiningClass() function in PHP

The IntlChar getCombiningClass() function is used to get the combining class value of a Unicode character. The combining class determines how a character interacts with adjacent characters in text rendering and normalization.

Syntax

int IntlChar::getCombiningClass(mixed $codepoint)

Parameters

• codepoint − An integer codepoint value, or a character encoded as a UTF-8 string.

Return Value

Returns the combining class of the character as an integer. Returns 0 for base characters and non-zero values for combining marks. Returns NULL on failure or for invalid input.

Example

The following example demonstrates getCombiningClass() with different character types −

<?php
   // Base character (space)
   var_dump(IntlChar::getCombiningClass(" "));
   echo "<br>";
   
   // Base character (letter A)
   var_dump(IntlChar::getCombiningClass("A"));
   echo "<br>";
   
   // Combining character (combining diaeresis)
   var_dump(IntlChar::getCombiningClass("\u{0308}"));
   echo "<br>";
   
   // Invalid input (string with multiple characters)
   var_dump(IntlChar::getCombiningClass("PQRST"));
?>

int(0)
int(0)
int(230)
NULL

Key Points

• Base characters return combining class 0

• Combining marks return non-zero values (typically 1-254)

• Input must be a single character or valid codepoint

• Multi-character strings return NULL

Conclusion

The getCombiningClass() function is useful for Unicode text processing, particularly when working with diacritical marks and text normalization. It returns 0 for base characters and positive integers for combining characters.