PHP gzuncompress() Function: Usage and Examples

Use gzuncompress() when you need to decompresses strings stored in the zlib compressed-data format in a PHP application. The examples below show the actual operation and its limitations.

What Is gzuncompress() in PHP?

Decompresses strings stored in the zlib compressed-data format. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

gzuncompress(string $data, int $max_length = ...): string|false

Parameters and return value: The parameter types, optional arguments, references, and return type are shown in the signature above. Optional parameters are marked with an ellipsis in this reference signature.

Example 1: Basic Usage

<?php

echo gzuncompress(gzcompress("Hello"));

Output:

Hello

Example 2: Different Input or Behavior

<?php

echo gzuncompress(gzcompress("Config"));

Output:

Config

Practical Example: Applying the Function

<?php

$content = "Backup metadata"; $packed = gzcompress($content); $unpacked = gzuncompress($packed); echo $unpacked === $content ? "Verified" : "Mismatch";

Output:

Verified

Important Behavior and Edge Cases

Untrusted compressed input can expand dramatically; validate limits before decompression.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Decompresses strings stored in the zlib compressed-data format.
• Untrusted compressed input can expand dramatically; validate limits before decompression.
• gzinflate() expects raw DEFLATE, while gzuncompress() expects zlib-wrapped data.

Use gzuncompress() for the specific operation demonstrated above. Check its prerequisites and handle failure conditions before using it with production data.