PHP File upload $_files error code

Starting with PHP 4.2.0, PHP returns a corresponding error code along with the file information array. The code can be found in the Error field in the file array generated when the file is uploaded, i.e. $_files[' userfile ' [' Error '].
Upload_err_ok
Its value is 0, no error occurred, file upload success.
Upload_err_ini_size
The value is 1, and the uploaded file exceeds the value of the Upload_max_filesize option limit in php.ini.
Upload_err_form_size
The value is 2, the size of the uploaded file exceeds the value specified by the Max_file_size option in the HTML form. Upload_err_partial
The value is 3 and the file is only partially uploaded.
Upload_err_no_file
The value is 4 and no files are uploaded.
Upload_err_no_tmp_dir
The value is 6 and the temporary folder cannot be found. PHP 4.3.10 and PHP 5.0.3 introduced.
Upload_err_cant_write
The value is 7 and the file write failed. PHP 5.1.0 introduced.
Note: The above values become PHP constants after PHP 4.3.0