PHP gzopen() Function: Usage and Examples

Use gzopen() when you need to opens a gzip file for compressed reading or writing in a PHP application. The examples below show the actual operation and its limitations.

What Is gzopen() in PHP?

Opens a gzip file for compressed reading or writing. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

gzopen(string $filename, string $mode, int $use_include_path = ...)

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

$path = tempnam(sys_get_temp_dir(),"gzip_"); $file = gzopen($path,"wb"); gzwrite($file,"Hi"); gzclose($file); echo filesize($path) > 0 ? "Written" : "Empty"; unlink($path);

Output:

Written

Example 2: Different Input or Behavior

<?php

$path = tempnam(sys_get_temp_dir(),"gzip_"); $file = gzopen($path,"wb"); gzwrite($file,"readable"); gzclose($file); $file = gzopen($path,"rb"); echo gzread($file,20); gzclose($file); unlink($path);

Output:

readable

Practical Example: Applying the Function

<?php

$path = tempnam(sys_get_temp_dir(),"gzip_"); $file = gzopen($path,"wb"); if ($file === false) throw new RuntimeException("Open failed"); gzwrite($file,"log entry
"); gzclose($file); echo "Log compressed"; unlink($path);

Output:

Log compressed

Important Behavior and Edge Cases

Use a binary mode such as wb or rb; verify open results and close handles.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Opens a gzip file for compressed reading or writing.
• Use a binary mode such as wb or rb; verify open results and close handles.
• fopen() opens ordinary streams; gzopen() handles gzip compression.

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