How to Use socket_clear_error to Clear Error Codes for a Specific Socket? Step-by-Step Guide

gitbox 2025-08-30

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<p><hr></p>
<p></span># How to Use socket_clear_error to Clear Error Codes for a Specific Socket? Step-by-Step Guide<span></p>
<p>In PHP network programming, working with sockets often involves encountering error codes, which help developers diagnose issues. <code>socket_clear_error

$socket: A valid socket resource.
Return value: Returns true on success, false on failure.

Use Cases

Clear error states before sending or receiving data multiple times.
Reset the state after handling socket exceptions to ensure smooth subsequent operations.
During debugging, to confirm whether an error still exists.

Step-by-Step Guide

1. Create and connect a socket

First, create a socket and try to connect to the target server.

<span><span><span class="hljs-variable">$socket</span></span><span> = </span><span><span class="hljs-title function_ invoke__">socket_create</span></span><span>(AF_INET, SOCK_STREAM, SOL_TCP);
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$socket</span></span><span> === </span><span><span class="hljs-literal">false</span></span><span>) {
    </span><span><span class="hljs-keyword">die</span></span><span>(</span><span><span class="hljs-string">"Unable to create socket: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">socket_strerror</span></span><span>(</span><span><span class="hljs-title function_ invoke__">socket_last_error</span></span><span>()));
}

</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">socket_connect</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>, </span><span><span class="hljs-string">"example.com"</span></span><span>, </span><span><span class="hljs-number">80</span></span><span>);
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$result</span></span><span> === </span><span><span class="hljs-literal">false</span></span><span>) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Connection failed: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">socket_strerror</span></span><span>(</span><span><span class="hljs-title function_ invoke__">socket_last_error</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>)) . PHP_EOL;
}
</span></span>

2. Check the current error state

If the connection fails, the socket will store an error code, which you can check using socket_last_error:

<span><span><span class="hljs-variable">$errorCode</span></span><span> = </span><span><span class="hljs-title function_ invoke__">socket_last_error</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>);
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Current error code: <span class="hljs-subst">$errorCode</span></span></span><span>" . PHP_EOL;
</span></span>

3. Clear the socket error

Use socket_clear_error to clear the error code and prevent it from affecting later operations:

<span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">socket_clear_error</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Socket error code has been cleared."</span></span><span> . PHP_EOL;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Failed to clear socket error code."</span></span><span> . PHP_EOL;
}
</span></span>

4. Operate on the socket again

After clearing the error, you can retry operations:

<span><span><span class="hljs-comment">// For example, send an HTTP request header</span></span><span>
</span><span><span class="hljs-variable">$request</span></span><span> = </span><span><span class="hljs-string">"GET / HTTP/1.1\r\nHost: example.com\r\nConnection: Close\r\n\r\n"</span></span><span>;
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">socket_write</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>, </span><span><span class="hljs-variable">$request</span></span><span>, </span><span><span class="hljs-title function_ invoke__">strlen</span></span><span>(</span><span><span class="hljs-variable">$request</span></span><span>)) === </span><span><span class="hljs-literal">false</span></span><span>) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Send failed: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">socket_strerror</span></span><span>(</span><span><span class="hljs-title function_ invoke__">socket_last_error</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>)) . PHP_EOL;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Request sent successfully."</span></span><span> . PHP_EOL;
}
</span></span>

5. Close the socket

After finishing operations, close the socket to free resources:

<span><span><span class="hljs-title function_ invoke__">socket_close</span></span><span>(</span><span><span class="hljs-variable">$socket</span></span><span>);
</span></span>

Conclusion

socket_clear_error is a useful tool for clearing socket error states, especially in complex network communications or long-lived connections. By following the above steps, you can effectively clear error codes, prevent accumulated errors from affecting your program, and improve the stability and reliability of network communication.

Mastering socket_clear_error will make your PHP socket programming more robust and efficient.

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