Problems with statically linking twitcurl library from VS2010 solution to VS2012 solution

Question

I am having trouble with integrating the twitter API twitcurl with my OpenFrameworks solution. The wiki instructions state to statically link the built library to my solution. Which is what I have done.

Steps I followed:

1) Downloaded the twitcurl library and built it on VS2012. The solution file was based in VS2010 so I had to update it within 2012. The build was as a release version.

2) Statically linked twitcurl.lib from its release folder to my OpenFrameworks solution.

Here are the errors I am getting after trying to build it:

1>twitcurl.lib(oauthlib.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj
1>twitcurl.lib(oauthlib.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.obj
1>twitcurl.lib(twitcurl.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj
1>twitcurl.lib(twitcurl.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.obj
1>twitcurl.lib(HMAC_SHA1.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj
1>twitcurl.lib(HMAC_SHA1.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.obj
1>twitcurl.lib(base64.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj
1>twitcurl.lib(base64.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.obj
1>twitcurl.lib(urlencode.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '0' doesn't match value '2' in main.obj
1>twitcurl.lib(urlencode.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MDd_DynamicDebug' in main.obj

I have learnt from some reading following these errors, that these are usually observed when trying to statically link a release version to a debug version. Subsequently I have tried all other combinations, tried building twitcurl in debug mode, and the other way around. Statically linking the debug version of the library gives me more errors, such as:

1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_slist_free_all referenced in function "public: bool __thiscall twitCurl::oAuthHandlePIN(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?oAuthHandlePIN@twitCurl@@QAE_NABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)
1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_easy_init referenced in function "public: __thiscall twitCurl::twitCurl(void)" (??0twitCurl@@QAE@XZ)
1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_easy_setopt referenced in function "public: __thiscall twitCurl::twitCurl(void)" (??0twitCurl@@QAE@XZ)
1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_easy_perform referenced in function "public: bool __thiscall twitCurl::oAuthHandlePIN(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?oAuthHandlePIN@twitCurl@@QAE_NABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)
1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_easy_cleanup referenced in function "public: __thiscall twitCurl::~twitCurl(void)" (??1twitCurl@@QAE@XZ)
1>twitcurl.lib(twitcurl.obj) : error LNK2019: unresolved external symbol __imp__curl_easy_getinfo referenced in function "public: bool __thiscall twitCurl::oAuthHandlePIN(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?oAuthHandlePIN@twitCurl@@QAE_NABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)
1>bin\SocialBuildings_debug.exe : fatal error LNK1120: 7 unresolved externals

What is the reason for this? and how can I find a workaround?

Thanks a lot for your help

Answer 1

So a couple of changes solved my issue:

1) In: Solution properties > C/C++ > Preprocessor > Preprocessor Definitions

Set:

_ITERATOR_DEBUG_LEVEL=2

(Tried to modify the actual dll first, but that failed, corrupted dll)

2) In: Solution properties > C/C++ > Code Generation > Runtime Library

Change to:

Multi-threaded DLL

I basically made sure these two fields were the same for both builds (which is what was causing the problem)