Binary safe string comparison

# strcmp

(PHP 4, PHP 5, PHP 7, PHP 8)

strcmp — Binary safe string comparison

### Description

strcmp(string `$string1`, string `$string2`): int

Note that this comparison is case sensitive. For case-insensitive comparison, see strcasecmp().

Note that this comparison is not locale aware. For locale aware comparison see strcoll() or Collator::compare()

### Parameters

`string1`

  The first string.

`string2`

  The second string.

### Return Values

Returns a value less than 0 if `string1` is less than `string2`; a value greater than 0 if `string1` is greater than `string2`, and `0` if they are equal. No particular meaning can be reliably inferred from the value aside from its sign.

### Changelog

Version | Description
--- | ---
8.2.0 | This function is no longer guaranteed to return `strlen($string1) - strlen($string2)` when string lengths are not equal, but may now return `-1` or `1` instead.

### Examples

Example #1 strcmp() example

`<?php
$var1 = "Hello";
$var2 = "hello";
if (strcmp($var1, $var2) !== 0) {
echo '$var1 is not equal to $var2 in a case sensitive string comparison';
}
?>`

### See Also

- Full string comparison
  - strcasecmp() - Binary safe case-insensitive string comparison
  - Collator::compare() - Compare two Unicode strings
  - strcoll() - Locale based string comparison
- Partial string comparison
  - substr_compare() - Binary safe comparison of two strings from an offset, up to length characters
  - strncmp() - Binary safe string comparison of the first n characters
  - strstr() - Find the first occurrence of a string
- Similar / other string comparison
  - preg_match() - Perform a regular expression match
  - levenshtein() - Calculate Levenshtein distance between two strings
  - metaphone() - Calculate the metaphone key of a string
  - similar_text() - Calculate the similarity between two strings
  - soundex() - Calculate the soundex key of a string

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