In PHP directory handling, how can we iterate over the contents of a directory using opendir, readdir, and closedir?

Introduction / Context:
PHP scripts often need to list files in a directory, for example to display uploaded images, process log files, or implement simple file managers. While high level functions like scandir exist, PHP also exposes lower level directory handling functions that mirror those in C, namely opendir, readdir, and closedir. This question asks how to use these functions together to iterate over directory contents in a structured way.

Given Data / Assumptions:

• A directory path exists on the server that is accessible to the PHP process.
• The script wants to enumerate all entries in that directory, usually skipping dot and dot dot.
• PHP provides functions for opening, reading, and closing directory handles.
• We want to follow the correct order of operations to avoid resource leaks.

Concept / Approach:
The typical pattern for reading a directory with these functions starts with opendir, which opens the directory and returns a handle. Then readdir is called in a loop with that handle to retrieve each entry name, one per call, until it returns false. After finishing the loop, closedir is used to release the handle and free resources. Inside the loop, you can use functions such as is_dir or is_file along with concatenated paths to process each item as needed. This pattern is similar in many languages and helps you manage directory iteration explicitly.

Step-by-Step Solution:
Step 1: Call opendir with the directory path, for example opendir("uploads"), and store the returned handle if the call succeeds.Step 2: Use a while loop and call readdir with the handle to fetch entry names such as file names and subdirectory names.Step 3: Inside the loop, skip entries that are dot or dot dot to avoid infinite recursion or confusing output.Step 4: For each remaining entry, build the full path and perform any needed processing, such as listing files or deleting old items.Step 5: After the loop finishes, call closedir with the handle to close the directory and free associated resources.

Verification / Alternative check:
To verify correct usage, you can compare the list of entries printed by your script with the output of an operating system directory listing command such as ls. They should match, apart from dot and dot dot if you skip them. Monitoring resource usage in long running scripts also shows that calling closedir prevents accumulation of open directory handles. Trying to call readdir without a valid handle will result in warnings, which confirms the importance of opening the directory first with opendir.

Why Other Options Are Wrong:
Option B suggests calling readdir before opendir, which is impossible because readdir requires a directory handle. Option C proposes deleting the directory before reading it, which contradicts the goal of listing its contents. Option D swaps the roles of closedir and opendir, which have specific and opposite purposes. These incorrect sequences do not follow the proper pattern for directory iteration in PHP.

Common Pitfalls:
A common pitfall is forgetting to close directory handles, especially in scripts that may open many directories or run for a long time, which can eventually exhaust system resources. Another mistake is not checking the result of opendir and continuing even when it fails due to missing directories or permission problems. Developers should always handle errors gracefully and avoid exposing internal directory structures directly to users. Combining opendir, readdir, and closedir with good error handling and filtering leads to robust directory traversal code.

Final Answer:
Correct answer: By calling opendir to get a handle, using readdir in a loop to read entries, and finally calling closedir to release the handle