vc2008构建和使用libcurl静态库

1>下载CURL源代码curl-7.26.0.zip

2>用VC2008/2005打开工程curl-7.26.0\lib\libcurl.vcproj,转换下工程并构建,可以直接编译成功!

3>新建个控制台工程测试下刚才编译的静态库libcurl.lib,可以在libcurl\curl-7.26.0\docs\examples目录找个简单的使用curl的例子,在这个工程选项Configuration Properties-| C/C++ -|General -|Additional Include Directories 路径中加入curl7.26\include, 在linker选项卡,指定静态库路径和静态库的名字libcurl.lib,代码如下

[cpp] view plain copy

#include "stdafx.h"
#include <Windows.h>
#include "curl/curl.h"
int _tmain(int argc, _TCHAR* argv[])
{
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "http://2345.com/?kduba");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
return 0;
}

此时cpp文件可以编译,但是链接报错

1>testcurl.obj : error LNK2001: unresolved external symbol __imp__curl_easy_init
1>testcurl.obj : error LNK2001: unresolved external symbol __imp__curl_easy_setopt
1>testcurl.obj : error LNK2001: unresolved external symbol __imp__curl_easy_perform
1>testcurl.obj : error LNK2001: unresolved external symbol __imp__curl_easy_cleanup

看样子根本没有链接静态库,虽然刚才指定了库的路径,确认库路径的名字没错,于是看了下curl_easy_init 这个函数的定义,

[cpp] view plain copy

CURL_EXTERN CURL *curl_easy_init(void);
CURL_EXTERN CURLcode curl_easy_setopt(CURL *curl, CURLoption option, ...);
CURL_EXTERN CURLcode curl_easy_perform(CURL *curl);
CURL_EXTERN void curl_easy_cleanup(CURL *curl);
/*
* Decorate exportable functions for Win32 and Symbian OS DLL linking.
* This avoids using a .def file for building libcurl.dll.
*/
#if (defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__)) && \
!defined(CURL_STATICLIB)
#if defined(BUILDING_LIBCURL)
#define CURL_EXTERN __declspec(dllexport)
#else
#define CURL_EXTERN __declspec(dllimport)
#endif
#else

看到这里于是明白了,如下操作:

在libcurl静态库工程选项Configuration Properties-| C/C++ -| Preprocessor 中加上BUILDING_LIBCURL宏
在测试工程选项Configuration Properties-| C/C++ -| Preprocessor 中加上CURL_STATICLIB宏,然后依次重新构建两个工程

发现测试工程链接不过

1>libcurl_MT.lib(easy.obj) : error LNK2001: unresolved external symbol __imp__WSACleanup@0
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__WSACleanup@0
1>libcurl_MT.lib(easy.obj) : error LNK2001: unresolved external symbol __imp__WSAStartup@8
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__WSAStartup@8
1>libcurl_MT.lib(tftp.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__WSAGetLastError@0
1>libcurl_MT.lib(select.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(asyn-thread.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(transfer.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(sendf.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__WSAGetLastError@0
1>libcurl_MT.lib(sendf.obj) : error LNK2001: unresolved external symbol __imp__send@16
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__send@16
1>libcurl_MT.lib(sendf.obj) : error LNK2001: unresolved external symbol __imp__recv@16
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__recv@16
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__getsockname@12
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__getsockname@12
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__getpeername@12
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__ntohs@4
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__ntohs@4
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__ntohs@4
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__WSASetLastError@4
1>libcurl_MT.lib(curl_addrinfo.obj) : error LNK2001: unresolved external symbol __imp__WSASetLastError@4
1>libcurl_MT.lib(select.obj) : error LNK2001: unresolved external symbol __imp__WSASetLastError@4
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__getsockopt@20
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__setsockopt@20
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__connect@12
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__bind@12
1>libcurl_MT.lib(tftp.obj) : error LNK2001: unresolved external symbol __imp__bind@12
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__bind@12
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__htons@4
1>libcurl_MT.lib(curl_addrinfo.obj) : error LNK2001: unresolved external symbol __imp__htons@4
1>libcurl_MT.lib(telnet.obj) : error LNK2001: unresolved external symbol __imp__htons@4
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__htons@4
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__closesocket@4
1>libcurl_MT.lib(connect.obj) : error LNK2001: unresolved external symbol __imp__socket@12
1>libcurl_MT.lib(curl_addrinfo.obj) : error LNK2001: unresolved external symbol __imp__freeaddrinfo@4
1>libcurl_MT.lib(curl_addrinfo.obj) : error LNK2001: unresolved external symbol __imp__getaddrinfo@16
1>libcurl_MT.lib(tftp.obj) : error LNK2001: unresolved external symbol __imp__sendto@24
1>libcurl_MT.lib(tftp.obj) : error LNK2001: unresolved external symbol __imp__recvfrom@24
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_unbind_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_msgfree
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ber_free
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_memfree
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_value_free_len
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_get_values_len
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_next_attribute
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_first_attribute
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_get_dn
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_next_entry
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_first_entry
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_search_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_simple_bind_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_init
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_set_option
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_err2string
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__listen@8
1>libcurl_MT.lib(ftp.obj) : error LNK2001: unresolved external symbol__imp__accept@12
1>libcurl_MT.lib(select.obj) : error LNK2001: unresolved external symbol ___WSAFDIsSet@8
1>libcurl_MT.lib(select.obj) : error LNK2001: unresolved external symbol __imp__select@20
1>libcurl_MT.lib(nonblock.obj) : error LNK2001: unresolved external symbol __imp__ioctlsocket@12
1>libcurl_MT.lib(curl_gethostname.obj) : error LNK2001: unresolved external symbol__imp__gethostname@8

谷歌了下, WSACleanup function msdn 是需要链接Ws2_32.lib,

同样的道理

1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_unbind_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_msgfree
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ber_free
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_memfree
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_value_free_len
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_get_values_len
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_next_attribute
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_first_attribute
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_get_dn
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_next_entry
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_first_entry
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_search_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_simple_bind_s
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_init
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_set_option
1>libcurl_MT.lib(ldap.obj) : error LNK2001: unresolved external symbol __imp__ldap_err2string

是少了Wldap32.lib

在libcurl静态库工程选项Configuration Properties-|Librarian -| Additional Dependencies 中加上依赖项Ws2_32.lib Wldap32.lib

再依次重编两个工程,就OK了

编译选项设为/MD时候,不需要添加Ws2_32.lib Wldap32.lib

小结:

1>对于开源代码的编译问题,还是要从代码入手,包括注释

2>静态库构建的时候很容易,但是要知道是不是成功的,还得编个测试工程才能知道是不是真的OK