PHP gzpassthru() Function: Usage and Examples

Use gzpassthru() when you need to outputs the remaining uncompressed contents of a gzip stream in a PHP application. The examples below show the actual operation and its limitations.

What Is gzpassthru() in PHP?

Outputs the remaining uncompressed contents of a gzip stream. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

gzpassthru($stream): int

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($file,"Hello"); gzclose($file); $file = gzopen($path,"rb"); gzpassthru($file); gzclose($file); unlink($path);

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Example 2: Different Input or Behavior

<?php

$path = tempnam(sys_get_temp_dir(),"gzip_"); $file = gzopen($path,"wb"); gzwrite($file,"ABCDE"); gzclose($file); $file = gzopen($path,"rb"); gzread($file,2); gzpassthru($file); gzclose($file); unlink($path);

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Practical Example: Applying the Function

<?php

$path = tempnam(sys_get_temp_dir(),"gzip_"); $file = gzopen($path,"wb"); gzwrite($file,"report body"); gzclose($file); $file = gzopen($path,"rb"); $count = gzpassthru($file); gzclose($file); echo "
Bytes: " . $count; unlink($path);

Result: Run the example in an environment that supports the function. Any values depending on operating-system state, installed extensions, process configuration, or network access must be checked on the target server.

Important Behavior and Edge Cases

Writes to the output stream; it does not return the extracted content as a string.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Outputs the remaining uncompressed contents of a gzip stream.
• Writes to the output stream; it does not return the extracted content as a string.
• gzread() returns uncompressed bytes; gzpassthru() sends them to output.

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