I am trying to calculate FFT on the stm32f4
The first errors I got were:
/home/mennesker/Workspace/stm/STM-mainopdracht2/main.c:111: undefined reference to `arm_cfft_radix4_init_f32'
/home/mennesker/Workspace/stm/STM-mainopdracht2/main.c:114: undefined reference to `arm_cfft_radix4_f32'
/home/mennesker/Workspace/stm/STM-mainopdracht2/main.c:117: undefined reference to `arm_cmplx_mag_f32'
/home/mennesker/Workspace/stm/STM-mainopdracht2/main.c:120: undefined reference to `arm_max_f32'
So I Thought I need to link the library because in the include files there are only .h files.
The libraries are in the same root folder so,
the .h files (arm_math.h and core_cm4.h) are in the folder:
/home/mennesker/Workspace/stm/STM32F4-Discovery_FW_V1.1.0/Libraries/CMSIS/Include/
The library arm_cortexM4b_math.lib is in folder:
/home/mennesker/Workspace/stm/STM32F4-Discovery_FW_V1.1.0/Libraries/CMSIS/Lib/ARM/
I tried many different variantions of paths where to put the library to link with using -l arm_cortexM4b_math.lib as linker option or -l <path to file> /arm_cortexM4b_math.lib
But I still get the error:
/usr/bin/../lib/gcc/arm-none-eabi/4.9.3/../../../../arm-none-eabi/bin/ld: cannot find -larm_cortexM4b_math.lib
I don't know where the linker looks and how this linking really works
Related
I am new to omnetpp. In my source file, I include zmq.h header and I can successfully make Makefile with opp_makemake --make-so -f --deep
Next, running make does not give any errors either
Creating shared library: out/gcc-release//libtictoc_r.so
So I am expecting, that zmq library has already been linked.
However, when I run
opp_run -l tictoc_r
I get
<!> Error: Cannot load library 'libtictoc_r.so': ./libtictoc_r.so: undefined symbol: zmq_strerror
Thus I doubt if zmq library had been linked correctly.
By the way, the header files for zmq are located in the standard directory, i.e.
find /usr/include/ -name "*zmq*"
returns
/usr/include/zmq.h
/usr/include/zmq_utils.h
/usr/include/zmq_addon.hpp
/usr/include/zmq.hpp
How could I solve my problem?
Using the header files does not say anything about where the actual shared object file is present. You must add -lzmq (or whatever the library is called) to your linker flags in the project.
The easiest way is to create a makefrag file in the source folder (where the Makefile is generated) and add
LDFLAGS += -lzmq
to it. The generated Makefile will include the makefrag file and that one can add to the linker flags. (the samples/sockets example does this too)
You can also add the required extra linker flags in the IDE's project properties dialog.
I downloaded Codeblocks to call GUROBI - an optimization package with libraries- from C. While building the example C code from GUROBI (See here), I get 15 errors in the form of:
.../main.c:32: undefined reference to `GRBloadenv#8'
.../main.c:32: undefined reference to `GRBreadmodel#12'
I already did the following:
In global compiler settings
Set Settings>Compiler>Search Directories>Compiler path to GUROBI's include folder (with .h files)
Set Search Directories>Linker path to GUROBI's lib folder (with .lib files)
Link libraries from Linker settings.
Did the same three steps above for the prject itself, i.e. Project>Build Options>...[same as Step 1]
Having spent the whole day, i cant find any solution. Any help is highly appreciated.
I'm working on Windows 10, Code::Blocks 17.12, and Gurobi 8.1.0
I did setup a C project with Eclipse Photon (4.8.0) for developing a program for the ESP-32. I did configure the IDE according to this official setup instructions.
Flashing the ESP-32 works fine. But as soon as I try to include header files from a sub folder, I run into troubles. I have set up a very simple project to illustrate the issue. The project consists of main.c, base/test.h and base/test.c, whereas the test.h and test.c files only contain one function with the signature void function1(void);.
When I try to call function1() in main.c, I get this error in main.c:
Undefined reference to function1()
Please compare to the attached screenshot, where everything is depicted.
How to solve this issue?
This is not a compiler, but rather a linker error.
Note, with #includeing a header file, you only make the external function known to the compiler. You also need to link to the external function during the linking stage. Make sure you include the compiled object file that contains function1 into the link.
Seems like you need to do proper linking.
If you are linking with a library, you need to specify:
The name of the library: Project\Settings\C C++ General\Paths and Symbols\Libraries
Location where the linker should search for this library:
Project\Settings\C C++ General\Paths and Symbols\Library Paths
Important: see Note.
If you are linking with object files, add those to:
Project\Settings\C C++ Build\Settings\Linker\Miscellaneous\Other objects
Note:
If your library name is, for example, libsomething.a, than you need to specify only something as the name; so omit lib prefix and .a suffix.
If your library is not prefixed with lib, then you need to add its name prefixed with :. For example, something.a should be added as :something.a.
I'm compiling a C++ static library using g++ via Cmake. I want to remove symbols relating to the internal implementation so they don't show up in nm. (See here and here for the same with shared libraries.)
This answer tells you how to do it on iOS, and I'm trying to understand what happens under the hood so I can replicate on Linux. They invoke ld with:
-r/--relocatable to Generate relocatable output---i.e., generate an output file that can in turn serve as input to ld.
-x/--discard-all: Delete all local symbols.
AFAICS the -r glues all the modules into one module, and then the -x removes symbols only used inside that module. Is that right?
It's not clear how the linker 'knows' which symbols will be exported externally? Does it rely on __attribute__((visibility("hidden/default"))) as in the .so case?
Edit: clearly I'm confused... I thought cmake invoked ld to link the .os into .a. Googled + clarified above.
Question still stands: how do I modify the build process to exclude most symbols?
(I'm on Windows.)
I try to build pysox. Therefore I built libsox (part of SoX). It is said, that pysox needs "libsox.so and libsox.a in your link path." When building libsox I got "libsox.a", "libsox-1.dll", "libsox.dll.a", "libsox.la", "libsox.lai" and many other strange files. When I placed "libsox.a" in my link path, the previously shown error disappeared. But now the build script has an error when it calls mingw32-gcc which says:
C:\Programme\MinGW\bin\mingw32-gcc.exe -shared -s build\temp.win32-2.7\Release\pysox\sox.o build\temp.win32-2.7\Release\pysox\sox.def -LC:\Programme\Python\libs -LC:\Programme\Python\PCbuild -lsox -lpython27 -lmsvcr90 -o build\lib.win32-2.7\pysox\sox.pyd
build\temp.win32-2.7\Release\pysox\sox.o:sox.c:(.text+0x3a96): undefined reference to `sox_get_encodings_info'
build\temp.win32-2.7\Release\pysox\sox.o:sox.c:(.text+0x5035): undefined reference to `sox_get_encodings_info'
build\temp.win32-2.7\Release\pysox\sox.o:sox.c:(.text+0x795d): undefined reference to `bcopy'
build\temp.win32-2.7\Release\pysox\sox.o:sox.c:(.text+0xa8b3): undefined reference to `bcopy'
collect2: ld returned 1 exit status
error: command 'mingw32-gcc' failed with exit status 1
The following attempts didn't work:
Placing "libsox-1.dll" in link path
Renaming it to "libsox.dll"
Renaming it to "libsox.so"
Placing all files generated along with "libsox.a" in link path
Do I really need an "so" file on Windows (how do I get it)? Or what has to be changed?
MinGW uses a static interface library for each dynamic link library (DLL). The libsox.dll.a library is the one you need at link time, i.e. that needs to be copied into the link path. libsox-1.dll is required in the PATH at runtime, but not needed at link time.
You don't need a .so file on Windows platforms. It seems that some symbols are missing from the static library libsox.a, or that a library is missing from the link line. Windows platforms do not allow unresolved symbols in DLLs, contrary to UNIX-like .so platforms. You might have to give the library containing sox_get_encodings_info and friends explicitly on the command line, remembering precedence on the linker line.