文章2：Using The libcurl C Interface（重要）

Using The libcurl C Interface There's the tutorial to start with, read the tutorial to get a general in-depth grip of what libcurl programming is all about. 有一篇概述文章，閱讀 the tutorial可以對於libcurl編程有一個深入的理解。 There are some example C source codes you can check out. They're not all-covering or even very extensive, but they might serve as a source of inspiration to start hacking. 另外，也可以在example C source codes學習libcurl。 Dig into the Symbols In Versions document to learn in which libcurl releases symbols were added or removed. Windows developers using Microsoft Visual Studio, might enjoy: Andrei Jakab's Using libcurl with SSH support in Visual Studio 2010 [PDF] Rosso Salmanzadeh's Using libcurl in Visual Studio [PDF] guide. Easy or Multi The easy interface is a synchronous, efficient, quickly used and... yes, easy interface for file transfers. Numerous applications have been built using this. The multi interface is the asynchronous brother in the family and it also offers multiple transfers using a single thread and more. Get a grip of how to work with it in the multi interface overview. easy interface是同步、高效、方便使用的，並且easy interface用於檔案傳輸。大量的應用程式都使用easy interface。 multi interface是非同步，提供了使用單個線程或多線程的多次傳輸。可以閱讀 the multi interface overview來理解multi interface是如何工作的 The Easy interface When using libcurl you init （libcurl - curl_global_init()）your easy-session and get a handle, which you use as input to the following interface functions you use. You continue by setting all the options you want in the upcoming transfer, most important among them is the URL itself. You might want to set some callbacks as well that will be called from the library when data is available etc. When all is setup, you tell libcurl to perform the transfer. It will then do the entire operation and won't return until it is done or failed. After the performance is made, you may get information about the transfer and then you cleanup the easy-session's handle and libcurl is entire off the hook! 在使用libcurl時，首先是初始化你的easy-session（簡單對話）並獲得一個handle，你可以使用這個handle作為接下來所用的介面函數的輸入。 接下來，你設定在upcoming transfer（接下來的傳輸，實際上就是指：接下來的這次串連）中你想要的選項，這些選項中最重要的就是URL。你也可以設定一些用於資料處理的一些回呼函數。 當這些都已經建立以後，你就可以執行這次transfer。它會執行所有操作，知道成功或者失敗才會傳回值。     See also the easy interface overview. curl_easy_init()  curl_easy_cleanup()  curl_easy_setopt()  curl_easy_perform()  curl_easy_getinfo() While the above functions are the main functions to use in the easy interface, there is a series of other helpful functions too including: 這些函數時在easy interface總經常用到的函數，還有一系列其他的有用的函數   curl_version() returns a pointer to the libcurl version string curl_getdate() converts a date string to time_t curl_formadd() build multipart form-data posts curl_formfree() free a previously built form POST curl_slist_append() builds a linked list curl_slist_free_all() frees a whole curl_slist as made with curl_slist_append() curl_easy_escape() URL encodes a string curl_easy_unescape() URL decodes a string All man pages are included in every release archive, in three different formats: man page, HTML and pdf. 所有的說明文檔都包含在每個發行版本裡，有三種形式：man page，HTML和pdf