1

So first I'll say I've looked in a ton of places to no success.

This PDF is where I started:
http://curl.haxx.se/libcurl/c/visual_studio.pdf
It seems outdated and does not include instructions for statically linking libraries. Or at least, I've tried following all of the instructions without any success.

I've tried following answers in
Installing LibCurl on Visual Studio 2010
error LNK2019: unresolved external symbol libcurl Visual studio
Building libcurl library in Visual Studio 2008
and other areas, but have not made any progress.

I will also say that I am NOT a Windows user by any stretch of the imagination. With that said I will lay out what I have done so far.

I am porting over an application I made in a Unix environment, specifically OSX. I've made a lot of progress with the exception of using libcurl. I need to statically link LibCurl so that the executable built by Visual Studio can be moved to other Windows devices as necessary without needing dlls for libcurl or MySQL (which I am also linking statically).

Anyway, with the gracious help of this repository:
https://github.com/blackrosezy/build-libcurl-windows
I was able to build libcurl onto my Windows device. This was a difficult process before I found this repository. Now I have a lib and an include folder. Inside the lib folder there are release and debug folders for dll and static builds each. Inside the static-release folder I have ONLY libcurl_a.lib. Inside the dll-release folder I have libcurl.dll, libcurl.lib, and libcurl.pdb.

I have gotten the program to SUCCESSFULLY build when dynamically linking from the dll-release folder. However, when I try to link statically from the static-release folder, I get 11 or so linker errors.

I have also included "libcurl_a.lib", "wldap32.lib", "ws2_32.lib", "winmm.lib", "libeay32.lib", and "ssleay32.lib" as dependencies.

In addition to all of this, I used NuGet to get libssh2.1.4.3.1, openssl.1.0.1.21, zlib.1.2.8.1 along with redist versions of all of these. I have included the following paths in my library directories as well:

path_to_libssh\build\native\lib\v110\Win32\Release\static\cdecl\<br>
path_to_openssl\build\native\lib\v110\Win32\Release\static\cdecl\<br>
path_to_zlib\build\native\lib\v110\Win32\Release\static\cdecl\<br>

I have also put the /include/ paths from these folders in my list of include directories.

In my preprocesser definitions I have "CURL_STATICLIB".

However, despite all of these steps that I have taken from multiple sources including some great answers on this site, and the PDFs and some answers on the LibCurl site, I am still having these linker errors.

As an example, one of the errors that I feel is slightly indicative (sorry I cannot copy and paste all of these errors from VS2013 that I can tell) says:

"error LNK2019: unresolved external symbol curl_easy_setopt referenced in function 'public:__cdecl Curler::Curler(char*)'(??0Curler@@QEAA@PEAD@Z)"

All of these errors are laid out similarly, pointing to some sort of __cdecl Curler function, with the error code LNK2019.

Anyway, my question is basically: what am I doing wrong? I am sorry if this is a vague question, or if you feel as though this is a repeat. But I can assure you that I have looked at a large list of Stack Overflow questions and other areas of the internet with no success, and I've begun to feel very lost. Things that seem to work for so many others I just cannot get to work. I think a large portion of the problem is my newness to Windows. If there is any other information that I can provide in order to help you help me, then I will gladly provide it. I really appreciate any help you can give me. Thanks.

Community
  • 1
  • 1
shovel_coder
  • 49
  • 1
  • 8

1 Answers1

0

First of all, thank you to user Pawan who edited my post; it was my first post and he helped make it up to standards aesthetically with the community so I know what to do in the future.

Anyway, I think I solved my problem. It's probably a bit of an edge case, but it worked for me anyway.

After a while, I decided to build libcurl for Win64 using Visual Studio. To do this, I grabbed the code from this helpful repository:
https://github.com/bagder/curl

I cloned it, and navigated to that directory. I then ran the following commands (this is in Powershell so I used unix-esque commands, but I did not use MinGW for this): 

mkdir build  
cd build  
cmake .. -G "Visual Studio 12 2013 Win64"

This built a Visual Studio Solution that I could open in Visual Studio 2013. In Visual Studio, I went to

Project Properties -> C/C++ -> Code Generation

And switched the Runtime Library option to "Multi-threaded (/MT)"

Then I built the project, which outputted the following files in the following path: 

path_to_pulled_code\build\lib\Release\libcurl.dll
path_to_pulled_code\build\lib\Release\libcurl_imp.exp
path_to_pulled_code\build\lib\Release\libcurl_imp.lib

So, now I had the lib file I needed. Now, in:

Project Properties -> Linker -> Input

I put "libcurl_imp.lib" and "ws2_32.lib" under Additional Dependencies.

As I've said before, I made sure that I had "CURL_STATICLIB" in Preprocessor Definitions. I also switched Runtime Library to "Multi-threaded (/MT)" for this project.

After all that, well, it compiled! For some reason I needed to copy libcurl.dll that the aforementioned Visual Studio build of bagder's repo made into my executable path in order for the solution to actually work. But it seems to be working now at least!

Thanks guys. Hopefully this answer will help anyone else who stumbles onto this problem like I did.

shovel_coder
  • 49
  • 1
  • 8