I have got a small async udp server - RiDE.
And i can't build it with CMake. When i trying to i get errors:
undefined reference to 'uv_default_loop'
undefined reference to 'uv_udp_init'
...(other libuv functions)
But when i build it with command like this:
gcc -std=c11 RiDE_server.h RiDE_server.cpp main.cpp -o main.x -Wall -luv
everything is ok.
I think that the problem is in src/CMakeLists.txt file, but i can't understand how to fix it. Path to libuv headers on my machine - /usr/include. Path to libuv shared libs - /usr/lib/x86-64-linux-gnu.
Run make VERBOSE=1. What linker command does it run? It must be missing -luv. To fix that, add something like this to your CMakeLists.txt:
target_link_libraries(foo uv)
Related
I am trying to run libFuzz on a C project that usually compiles to an executable. The examples I found for libFuzz almost exclusively link with a library, i.e. a mylibary.a file. So I compiled the project with the normal Makefile, and combined the generated object files into a library with ar rcs a.o b.o etc.. Now I want to link this library file with the fuzzing target using clang++, but the linker is not able to find the implementation of the function I want to fuzz.
The command I use for linking inside the src directory of the project is
clang++ -Wall -fsanitize=fuzzer -Wno-cpp -Wpedantic -std=c++11 -O2 -g -I/usr/include/libxml2 -g -O2 -rdynamic -o fuzzing libmylib.a fuzztarget.cc -lcurl -lxml2 -I.
The error I get is "Undefined reference to function_xy()"
So the compiler finds the import of the function but not the implementation of it.
I am new to clang and generally building complex C projects so all help is greatly appreciated. Thank you!
I tried compiling the project with the included Makefile, then combining the generated object files into a .a library and finally linking the library with my fuzzing target.
The error you got is about linking, not the LibFuzzer. If you can compile and link your file without implementing function in LLVMFuzzerTestOneInput, then the fuzz-target should work: Include header in your code, call the function, compile file and link with libraries. Please check the order of include path, file, linked libraries. Be careful with the option of optimization (-O2), sometimes the fuzzer does not give crash with this option.
I'm trying to compile a simple unit test on my windows machine.
When I'm trying to compile my test I'm using the shared library flag.
gcc -c -L./bin/ -lcmocka .\Test.c .\src\some_module.c
gcc .\Test.o .\some_module.o -o main
But the second line throws this error:
undefined reference to `_cmocka_run_group_tests'
However, if I'm compiling using directly the cmocka.c file which I downloaded from their git it works fine:
gcc -c .\lib\cmocka.c .\Test.c .\src\some_module.c
gcc .\Test.o .\some_module.o .\cmocka.o
What am I doing wrong in the first compilation?
In addition, I would happy to understand the difference between the two compilations. Which one is the better practice?
Thank you
In order to compile your code, the compiler does not need to know where to look for the library. It's enough if the compiler "finds" the declarations of the functions which are usually in the header files provided by the library.
This step is done in the first line of your compilation procedure (maybe you need to specify the folder to the header files by adding -Ipath/to/headers/):
gcc -c .\Test.c .\src\some_module.c
The library itself is "combined" with your code during the linking step, which is done during your second compilation step. Here you need to specify the library (and its path via -Lpath/to/library, if the linker does not find the library on its own):
gcc .\Test.o .\some_module.o -o main -L./bin/ -lcmocka
You should definitely not use your second approach and compile the library by yourself.
It is my first time trying to link external libraries to a C file. I read that I can use a Makefile and this is what I have:
all: src/main.c
gcc src/main.c -o main.exe -IC:\src\C\GameTry\dependencies\include -LC:\src\C\GameTry\dependencies\lib -lglfw3 -lgdi32 -lglew32s
clean:
rm *.o
The reason I included -lgdi32 is beacuse the official glfw documentation states that:
When using MinGW to link an application with the static version of GLFW, you must also explicitly link with gdi32
This makefile works but OpenGL throws the warning corrupt .drectve at end of def file repeatedly many times and it throws undefined reference to '__security_cookie' error may times aswell which causes the program to not compile.
I have looked all arround the internet and haven't been able to find an answer. I believe these errors have something to do with the default MSVN libraries but I'm not sure
If you have libglfw3.a that matches your compiler and platform (make sure to not mix win32 and win64), then a .def file should not be needed.
Somehow the linker is picking up a .def file anyway.
If there is a .def for glfw3, can you try to remove or rename it and try again?
I installed the hidapi library from Signall11 on my windows10 pc (using minGW). But now I'm having some trouble actually getting it to work with gcc. I have some main.c file in which I include the hidapi.h file. My gcc command looks like
gcc main.c
I'm not sure where I'm going wrong because whenever I try to run this command I get an undefined reference error to some function that is defined in the hidapi.h file.
A full compile command for a project using hidapi is like this:
gcc -o your_app your_app.c -lhidapi-hidraw
It's not enough to include #include "hidapi.h" in the C-code, which does let gcc compile. You also need -lhidapi-hidraw to link with the library. I.e. compiling is in fact a 2 step process.
I started experimenting with C/C++ the other day because I needed it for reading level-4 MAT-files without needing to purchase the Matlab editor or compiler. So I found just the library that I needed but I'm not familiar with C or C++ at all so I'm a beginner with those two languages. Anyhow I need to include the 'matio' library. I've tried many things but I've had no luck.
I right clicked on the C/C++ project > properties > C/C++ General > Paths & Symbols > GNU C and added the path to the matio library.
I also went to C/C++ Build > Settings > Tool settings > GCC C Compiler > Includes and added the path there aswell.
Since I'm not any good with makefiles yet I did not specify my own makefile, instead I chose a executable project.
When I try to build my project it complains about a function called 'Mat_Open' in the matio library. When I hover over it, it says "undefined reference to 'Mat_Open'" the header 'matio.h' seems to work fine but it can't refer to 'Mat_Open' for some reason.
How do I solve this?
EDIT:
Here is the whole build console output.
10:42:52 **** Incremental Build of configuration Debug for project Project ****
Info: Internal Builder is used for build
gcc -IC:/matio-1.5.2/src -O0 -g3 -Wall -c -fmessage-length=0 -o CComponent.o "..\\CComponent.c"
gcc -Xlinker -lm -o Project.exe CComponent.o -lC:/matio-1.5.2/src
c:/mingw(x64)/bin/../lib/gcc/x86_64-w64-mingw32/4.8.0/../../../../x86_64-w64-mingw32/bin/ld.exe: cannot find -lC:/matio-1.5.2/src
collect2.exe: error: ld returned 1 exit status
10:42:53 Build Finished (took 330ms)
This is not necessarily an answer but may be useful for a comparison.
First of all, where did you install it? If your using Linux or Mac OSX you will want to install in the system directories (not sure about Windows). I use OSX so in my makefile (by the way I use Qt):
LIBS += -L/usr/local/lib/ -lmatio
INCLUDEPATH += /usr/local/include
Then of course, in the *.h files of my source I use:
#include "matio.h"
But I assume you have already tried that?