/Mingw32/bin/ld.exe: cannot find -llibcurl?

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I am trying to compile Libcurl for my project but I am getting below error.

g++ -g -o Main.exe Main.o L"C:\Test\src\WebSocket\lib" -D_WIN32_WINNT=0x0601 -DWINVER=0x0601 -DCURL_STATICLIB -llibcurl

/mingw32/bin/ld.exe: cannot find -llibcurl

When I built libcurl usinf mingw32 I got two files i.e. libcurl.a, libcurl.la.
I added both files under <c:\test\src\websocket\lib>.
I am not sure why linker is unable to link these libraries.

Can anybody with good compiler and libcurl understanding help for this?

What I have tried:

Initially I was getting error like :
main.cpp:11: undefined reference to __imp__curl_easy_init'
main.cpp:13: undefined reference to __imp__curl_easy_setopt'
main.cpp:14: undefined reference to __imp__curl_easy_perform'
main.cpp:17: undefined reference to __imp__curl_easy_cleanup'

Then I realized I need to link my libcurl library which I did as below:

WS_DIR = "C:\Test\src\WebSocket\curl"
WS_LIB = "C:\Test\src\WebSocket\lib"

g++ -c -std=c++11 -g -fpermissive src/Main.cpp -I${WS_DIR} -D_WIN32_WINNT=0x0601 -DWINVER=0x0601 -L${WS_LIB} -DCURL_STATICLIB -llibcurl

I have compiled cURL using mingw32.

But now i am facing linking issue.
please help.

Posted 14-Mar-16 21:09pm

Member 10305620

Updated 15-Mar-16 0:25am

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Richard MacCutchan · Answer 1 · 2016-03-15T00:25:00

Solution 1

If you look closely at the Link Options - Using the GNU Compiler Collection (GCC)[^], you would see that the option should be -lcurl.

Posted 15-Mar-16 0:25am

Richard MacCutchan

Comments

Member 10305620 15-Mar-16 6:44am

@Richard: Yeah I found out how silly the mistake was. Gosh !! I hate these stupid mistakes I make.

But now I am facing old issue again with all sort of "undefined reference".
It's so annoying to get a lib compiled with project in c++.
Below are the errors, Please help or put in me right direction as it's pretty urgent for me :(

\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x158): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x30a): undefined reference to `getpeername'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x313): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x377): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x3f0): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x419): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x515): undefined reference to `recv'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x6ba): undefined reference to `socket'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x861): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0xbbb): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0xd8b): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0xdfb): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0xf0d): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-connect.o):(.text+0x137d): more undefined references to `__errno' follow
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x7a): undefined reference to `poll'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0xa3): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x18d): undefined reference to `poll'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x197): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x205): undefined reference to `poll'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x31d): undefined reference to `poll'
\src\WebSocket\lib\libcurl.a(libcurl_la-select.o):(.text+0x329): undefined reference to `__errno'
\src\WebSocket\lib\libcurl.a(libcurl_la-nonblock.o):(.text+0x1d): undefined reference to `fcntl'
\src\WebSocket\lib\libcurl.a(libcurl_la-nonblock.o):(.text+0x3e): undefined reference to `fcntl'
\src\WebSocket\lib\libcurl.a(libcurl_la-nonblock.o):(.text+0x5e): undefined reference to `fcntl'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0xf1): undefined reference to `_imp___ctype_'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x64b): undefined reference to `sigprocmask'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x6e5): undefined reference to `sigaction'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x722): undefined reference to `sigaction'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x748): undefined reference to `alarm'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x765): undefined reference to `sigprocmask'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x771): undefined reference to `setjmp'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x851): undefined reference to `alarm'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x875): undefined reference to `sigaction'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x888): undefined reference to `alarm'
\src\WebSocket\lib\libcurl.a(libcurl_la-hostip.o):(.text+0x8be): undefined reference to `alarm'
\src\WebSocket\lib\libcurl.a(libcurl_la-cookie.o):(.text+0x3fe): undefined reference to `strtok_r'
\src\WebSocket\lib\libcurl.a(libcurl_la-cookie.o):(.text+0x47c): undefined reference to `strtok_r'
\src\WebSocket\lib\

Richard MacCutchan 15-Mar-16 6:47am

You are missing some other libraries, at a guess some of the standard ones. Google the name of the missing items in the messages above and that should lead you to the names of the required libraries.

Member 10305620 15-Mar-16 6:56am

@Richard: I have spent whole day figuring out and looking through google but couldn't find any useful information :(

Richard MacCutchan 15-Mar-16 7:47am

Hmm, you're right, the Linux man pages do not seem to identify the library required for each system call, which is rather useless. At the very least you need that standard c library (-lc). As for the others I would try one of the Linux support forums.

As an aside, I do wonder why you are using gnu to create a Windows program.

Member 10305620 15-Mar-16 23:44pm

Exactly. My requirement is to write a WebClient for a server.
But c++ doesn't have inbuilt support as such and while going through many posts I found this library.
But I am just following the step mentioned in the library documentation for compiling it along side my application.
Could suggest any simple plug and play kind of library which I can directly use without any dependency, you know like some header type library.

Richard MacCutchan 16-Mar-16 5:30am

plug and play kind of library
I have no idea what that would be. Just about all gnu software is buildable for the platform you want it to run on, which is good and bad in equal measure. However, you need to ensure that you include all dependent libraries as well, and the only way to find them is by going through the gnu documentation. It's a long time since I used gnu but I am fairly sure it needs libc at the very least.

Member 10305620 16-Mar-16 7:54am

Agreed, I guess its going to be a tough task to look into dependencies :(

Anyway Thanks, I will update when I solve this issue.(I hope I find solution fast or else its going to cost me :|)

Richard MacCutchan 16-Mar-16 8:36am

It should not be too difficult. Add the c and curl libraries for a start. Then look at the linker error messages to see what is still missing. Search Google for each of the missing items and see if you can find a document (Linux man pages or GNU reference) which tells you which library to choose. If that search does not help then look at the names of all the installed libraries and try a few intelligent guesses. I know that is not very scientific but it seems the only way forward.

Richard MacCutchan 16-Mar-16 5:32am

In all your googling did you never find https://msdn.microsoft.com/en-us/library/windows/desktop/aa383630(v=vs.85).aspx?

Member 10305620 16-Mar-16 7:51am

My client app need to be platform independent which means i need a lib which can work on windows as well as linux.
Hence, above like is not much of the use for me.