What is purpose of CURL_UPLOAD option in CURL

if upload file , i can use $data = array('file' => '@/home/user/test.pn开发者_Python百科g'); then what is purpose of CURL_UPLOAD option ?

Uploading a file to a remote server.

curl supports many different ways of uploading, using a large amount of different protocols.

This array-approach shown above is only used for doing HTTP multipart formposts. If you for example rather want a HTTP PUT, or upload with FTP, FTPS or SFTP etc, that's the option for you...