Linker Error (LNK2019) undefined reference to __imp_

Question

I am working on open62541 open source project.I have built the project using Cmake as mentioned here at the following webpage open62541.org and generated the open62541.c ,open62541.h files in the project's build folder.Then I created a new folder called C_project inside the build folder and copied the generated files into this folder.

Now I am trying to build a minimal server(C_Project/myServer.c) by following the steps given at the following page open62541/sever.I am getting the following link errors.

C:\SPB_Data\open62541\build\C_Projects\OPC_UA>cmd /c gcc -std=c99 open62541.c myServer.c -lws2_32 -o myServer.exe > output.txt
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0x98): undefined reference to `__imp_UA_ServerConfig_setMinimalCustomBuffer'
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0xd8): undefined reference to `__imp_UA_Log_Stdout'
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0x132): undefined reference to `__imp_UA_Server_new'
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0x146): undefined reference to `__imp_UA_Server_getConfig'
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0x165): undefined reference to `__imp_UA_Server_run'
C:\Users\PAVAN-~1\AppData\Local\Temp\cc1s9pOw.o:myServer.c:(.text+0x178): undefined reference to `__imp_UA_Server_delete'
collect2.exe: error: ld returned 1 exit status

I used the following command to build the project:

$ gcc -std=c99 open62541.c myServer.c -o myServer

I tried to find the solutions for this by searching in the web. The only thing that I could get out of that is it might be a error due to dll files. Kindly help.

Answer 1

-open62541.lib specifies that the result of compilation should be written to file pen62541.lib.

And -o myServer.exe says that it should be written to myServer.exe instead.

And GCC will then ignore the first output file name.

Solution: remove the - from the library name.

Answer 2

I had similar problem as you when I made the CMake build with BUILD_SHARED_LIBS on. For me it was working when I installed open62541 with CMake options UA_ENABLE_AMALGAMATION on and UA_NAMESPACE_ZERO full (rest default)

I compiled with the command

gcc -std=c99 myserver.c open62541.c -o server -lws2_32

Inside the selected folder are just the files open62541.c/.h and myserver.c