ftp_async_fput() uploads the data from the file pointer fp until end of file. The results are stored in remote_file on the FTP server. The transfer mode specified must be either FTP_ASCII or FTP_BINARY. The difference between ftp_fput() is that this function uploads the file asyncronously, so you can do other things in your program while the file is uploadde.
Returns TRUE on success, FALSE on error.