CURL----- Client URL Library Functions

简介：
PHP supports libcurl, a library created by Daniel Stenberg, that allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols. libcurl also supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading (this can also be done with PHP's ftp extension), HTTP form based upload, proxies, cookies, and user+password authentication.
These functions have been added in PHP 4.0.2.
需求：
In order to use the CURL functions you need to install the
CURL
package. PHP requires that you use CURL 7.0.2-beta or higher. PHP will not work with any version of CURL below version 7.0.2-beta. In PHP 4.2.3, you will need CURL version 7.9.0 or higher. From PHP 4.3.0, you will need a CURL version that's 7.9.8 or higher. PHP 5.0.0 will most likely require a CURL version greater than 7.10.5
安装：
To use PHP's CURL support you must also compile PHP --with-curl[=DIR] where DIR is the location of the directory containing the lib and include directories. In the "include" directory there should be a folder named "curl" which should contain the easy.h and curl.h files. There should be a file named libcurl.a located in the "lib" directory. Beginning with PHP 4.3.0 you can configure PHP to use CURL for URL streams --with-curlwrappers.
注意 Win32 Users: In order to enable this module on a Windows environment, you must copy libeay32.dll and ssleay32.dll from the DLL folder of the PHP/Win32 binary package to the SYSTEM folder of your Windows machine. (Ex: C:\WINNT\SYSTEM32 or C:\WINDOWS\SYSTEM)
不过现在有个window版本不需要这个操作了，直接打开php.ini里的dll，然后重启web服务器即可支持。