PHP strncmp() Function

The PHP strncmp() function is used to perform binary safe case-sensitive string comparison of the first n characters of two strings.

This function is same as strcmp() function, except this function has one more parameter which is used to specify number of (upper limit of the) characters from each string to be used in the comparison.

Syntax

strncmp(str1, str2, length)

Parameters

Return Value

Returns the following value:

• Returns a number less than 0, when first string is less than second string.
• Returns 0, when both strings are equal.
• Returns a number greater than 0, when first string is greater than second string.

Example:

In the example below, strncmp() function is used to compare two strings and returns values based on the value of two strings.

<?php
//returns 0 as first 5 characters 
//of both strings are same
echo "result1: ".strncmp('Hello Jo', 'Hello Kim', 5)."\n";

//returns positive number as first unmatched character
//of first string is greater than that of second string
echo "result2: ".strncmp('World', 'Hello', 5)."\n";

//returns negative number as first unmatched character
//of first string is less than that of second string
echo "result3: ".strncmp('Hello', 'World', 5)."\n";
?>

The output of the above code will be:

result1: 0
result2: 1
result3: -1