Where does PHP save temporary files during uploading?

[pspuser007]

I am using XAMPP on Windows. By printing \[code\]$_FILES["file"]["tmp_name"]\[/code\], it seems that the temporary file was saved at C:\xampp\tmp\phpABCD.tmp. But I cannot see it on the filesystem of the server. However, the file can be moved or copied via \[code\]move_uploaded_file()\[/code\], \[code\]rename()\[/code\], or \[code\]copy()\[/code\]. So where does PHP actually save temporary files during uploading?