Permission denied in /opt/lampp/htdocs/ when writing a file in PHP - php

Question

When a user creates a profile and uploads a profile picture, the PHP "move_uploaded_file" function is used to move a temporary copy of this image to the project directory.
While my current code works perfectly fine on my Windows 10 machine, it doesn't work on my Mac because of incorrect file permissions.
I have already tried the method provided in other answers and nothing changes after running the terminal command:
sudo chmod 644 /opt/lampp/htdocs/yourfolder
This is true for any variation including:
sudo chmod -R 777 /opt/lampp/htdocs/yourfolder
Note that I DO have admin permissions on the laptop
Other users have stated that these commands have fixed their problems, so I suspect that mine is different.
PHP Code Snippet:
$username = $_POST["username"];
$password = $_POST["password"];
$ext = null;
/* Debugging information
echo $_FILES["profile_pic"]["name"]."<br>";
echo $_FILES["profile_pic"]["tmp_name"]."<br>";
echo $_FILES["profile_pic"]["size"]."<br>";
echo $_FILES["profile_pic"]["error"]."<br>";
*/
if (strrpos($_FILES["profile_pic"]["name"], ".jpg") != null || strrpos($_FILES["profile_pic"]["name"], ".jpeg") != null) {
$ext = ".jpg";
};
if (strrpos($_FILES["profile_pic"]["name"], ".png") != null) {
$ext = ".png";
};
$path = __DIR__ . "\data\users\images\\" . uniqid() . $ext;
if (move_uploaded_file($_FILES["profile_pic"]["tmp_name"], $path)) {
echo("File successfully uploaded");
} else {
echo("Upload failed");
};
Returned: Upload failed
Error thrown:
move_uploaded_file(/opt/lampp/htdocs/Test-Site\data\users\images\5c1dadd52bb71.jpg): failed to open stream: Permission denied in /opt/lampp/htdocs/Test-Site/signup_confirm.php on line 27
Expected: user profile picture is inserted into the .../htdocs/Test-Site/data/users/images folder
Actual: above error about incorrect file permissions is thrown

Answer 1

The reason for the error is that I was using incorrect directory separators ("\" instead of "/" for Mac). Changing these made the profile picture move to the intended location.