Controlling an Asynchronous URL Upload or Download

You can use the functions in this section to control the progress of a file upload or download. The functions described in this section are more flexible than URLSimpleDownload and URLSimpleUpload and they are asynchronous, returning control to your application immediately.

Your application can use the following functions regardless of whether it is uploading or downloading data:

URLOpen to start the process of downloading data from a URL to a file or uploading data from file to a URL. Your application may then call the other functions described in this section to control the download or upload process.
URLAbort terminates an upload or download process that was started by calling URLOpen .

Your application may use the following functions when it is downloading data:

URLGetDataAvailable determines the amount of data that your application can retrieve from buffers.
URLGetBuffer retrieves the next buffer of data in a download operation.
URLReleaseBuffer releases the buffer obtained by a call to URLGetBuffer .