How to find original modification time of the uploaded file

When a file is uploaded  filemtime($_FILES['file']['tmp_name']) gives me the time of  the upload (!)

How can find the find original modification time of the uploaded file?
Thank you
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Ray PaseurCommented:
You probably cannot find this from information on the server.  The file was modified (or stored, created, etc.) before it was uploaded.  The file upload process does not communicate the file history information See $_FILES to learn what information is sent along with the uploaded file.

For those of us who care about this sort of thing, there is version control.  The most popular tool is Git.  You will get a durable record of the date/time of any "commit" to the repository.
Vimal DMSenior Software EngineerCommented:

1. The same php function can be used to find out the last modification time of a file. Below is the example for it,

$filename = 'somefile.txt';
if (file_exists($filename)) {
    echo "$filename was last modified: " . date ("F d Y H:i:s.", filemtime($filename));

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2. Use filectime. For Windows it will return the creation time, and for Unix the change time which is the best you can get because on Unix there is no creation time (in most filesystems).
Ray PaseurCommented:
The same php function can be used to find out the last modification time of a file.
But only if the modification took place on the server.  Here are some scenarios:

File "X" modified two hours ago on the client machine, then uploaded to the server.  Server thinks the file was modified at the time of upload.

File "Y" modified on the client, then modified again.  Never uploaded.  Server thinks the file does not exist.

File "X" has not been modified for weeks, but gets uploaded and overwritten.  The server thinks the file is newly modified.  The contents might be an exact match between server and client, but the dates will not match at all.

These kinds of problems arise because the client and server are two different machines with two different file systems.  This is exactly the sort of problem that is mitigated by a distributed version control system like Git.

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myyisAuthor Commented:
Thank you.
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