What does the error message "failed to open stream: Die Operation ist jetzt in Bearbeitung" indicate in PHP?

The error message "failed to open stream: Die Operation ist jetzt in Bearbeitung" in PHP indicates that the file or resource being accessed is currently in use or locked by another process. To solve this issue, you should ensure that the resource is not being accessed by any other process and that proper file handling techniques are used to prevent conflicts.

$filename = "example.txt";

// Check if the file is accessible
if (is_readable($filename)) {
    // Open the file for reading
    $file = fopen($filename, "r");
    
    // Read the contents of the file
    $content = fread($file, filesize($filename));
    
    // Close the file
    fclose($file);
    
    // Output the file content
    echo $content;
} else {
    echo "Error: Unable to open file for reading.";
}