PHP getprotobyname() Function: Usage and Examples

Use getprotobyname() when you need to resolves a network protocol name into its numeric protocol identifier in a PHP application. The examples below show the actual operation and its limitations.

What Is getprotobyname() in PHP?

Resolves a network protocol name into its numeric protocol identifier. The exact signature supported by your installation depends on its PHP version and enabled extensions.

Its syntax is:

getprotobyname(string $protocol): int|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

var_dump(getprotobyname("tcp"));

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

var_dump(getprotobyname("udp"));

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

$protocol = "tcp"; $number = getprotobyname($protocol); echo $number === false ? "Unknown" : "Protocol number: " . $number;

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

Protocol service databases vary by platform; unknown names return false.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Resolves a network protocol name into its numeric protocol identifier.
• Protocol service databases vary by platform; unknown names return false.
• getprotobynumber() performs the reverse lookup.

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