I'm trying to compile a shared library with cmake to use it further with the "dlfcn" lib in a C program. I am on Windows with Cygwin, but I don't know how to use "dlfcn" with the shared libraries of windows (.dll and .dll.a) and my teammates are using Linux. So I would like to create not .dll and .dll.a libraires but a .so library. I'm a beginner with cmake, is there a possibility to do it or am I obliged to install a Linux VM ?
So, thanks to #Florian, I finally made it. To the ones who want to know how it works, it's quite simple :
Create a new .cmake file :
# this mandatory command will be the one that will make your cross-compiling work
set(CMAKE_SYSTEM_NAME Linux)
# indicate compilers (optional)
set(CMAKE_C_COMPILER gcc)
set(CMAKE_CXX_COMPILER g++)
When calling your cmake command, add an argument like this :
cmake -DCMAKE_TOOLCHAIN_FILE=./myToolChainFile.cmake ..
Related
I have installed GCC cross compiler for Raspberry Pi to my Ubuntu 20.04 to opt folder. Now When I create new cross compile project I have list of include in my Eclipse project explorer:
/opt/gcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/arm-none-linux-gnueabihf/include
/opt/gcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/arm-none-linux-gnueabihf/libc/usr/include
/opt/gcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/lib/gcc/arm-none-linux-gnueabihf/10.2.1/usr/include
/opt/gcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/lib/gcc/arm-none-linux-gnueabihf/10.2.1/usr/include-fixed
How Eclipse knows these include folders?
What is purpose of all of these folders? What kind of includes they are defined for?
Suppose I need to use SDL2 library. Where I should place it's header and binary?
As explained in this article (which is a little dated) https://www.eclipse.org/community/eclipse_newsletter/2013/october/article4.php CDT will try to detect built-in compiler symbols and include paths running the compiler with special options and parse the output of this special run. The command will be probably something like: arm-linux-gnueabihf-cpp -v /dev/null -o /dev/null supposing the compiler you are using is arm-linux-gnueabihf-gcc.
All these folders contains include files like stdio.h , stdlib.h ... of libc , libm ... and also some arm specific header files.
If you are not 100% sure, install the cross compiled in a directory all by itself and add the include directory to your eclipse project.
I have received an SDK that is used to build c++/c applications for an embedded linux device. This is all new to me so some of my terminology may be wrong.
I followed their instructions and the SDK installs on my linux (ubuntu) system in /opt/. The compiler they are using appears to be arm-poky-linux-gnueabi-gcc. Part of their SDK sets some environment variables, like $CC and CPP for compiling C/C++. The environment variables run something like arm-poky-linux-gnueabi-gcc -march=armv7-a (and a bunch of other flags).
My question is: how can I utilize this using cmakelists/cmake? I currently have an entire library and application that is built around cmake.
The SDK should come with a toolchain file for cmake (for example named toolchain.cmake).
When you first call your cmake, you force it to use the SDK like this:
cmake -DCMAKE_TOOLCHAIN_FILE=/opt/???/toolchain.cmake.
I'm trying to build libmcrypt library to use it with my project. It happened so, that they do not provide any kind of assistance.
First I've faced a problem with -no-undefined flag for gcc which is not further supported. I've replaced -no-undefined with -Wl,-no-undefined in makefiles and it does the trick.
But anyway I'am having problems. Lib is builded in .a files. I can see them in my C:\MinGW\msys\1.0\local\lib folder (it is analogue for /usr/local/lib folder in MinGW). But I need .dll library, not static .a .
So: what else must I change in makefiles to make MinGW build dll with header and debug info for it?
I'm trying to compile a library (dxflib) for use in windows using cygwin.
I'm loosely following the instructions found here: http://www.ribbonsoft.com/doc/dxflib/2.5/reference/dxflib-reference-manual.pdf
I can get it to compile to make a .a library (ie a unix static library), using 'make' but obviously I'm using cygwin because I want to compile a .lib for use in windows.
When I try to use 'MinGW32-make' (or any other derivative I can think of) cygwin claims that it doesn't exist. I've reinstalled all options with mingw or gcc or g++ remotely in their name in cygwin.
Does anybody know how to get it to compile from the makefile to produce a .lib? Thanks.
[Shamelessly cross-posted from the CMake help list]
I'm trying to create binaries as statically as possible. The fortran code I've got has got X11 and quadmath as dependencies, and I've come across a number of issues (maybe each of these issues should be in a different question?):
My variables are currently
set(CMAKE_LIBRARY_PATH /usr/X11/lib /usr/X11/include/X11 ${CMAKE_LIBRARY_PATH})
find_package(X11 REQUIRED)
find_library(X11 NAMES X11.a PATHS /usr/X11/include/X11/ /usr/X11/lib)
find_library(X11_Xaw_LIB NAMES Xaw Xaw /usr/X11/include/X11/ /usr/X11/lib ${X11_LIB_SEARCH_PATH})
find_library(Xaw Xaw7 PATHS ${X11_LIB_SEARCH_PATH})
set(CMAKE_LIBRARY_PATH /usr/lib/gcc/x86_64-linux-gnu/4.7 /usr/lib/gcc/x86_64-linux-gnu/4.7/x32 /usr/lib/gcc/x86_64-linux-gnu/4.7/32 ${CMAKE_LIBRARY_PATH})
find_library(quadmath NAMES quadmath.a)
set(BUILD_SHARED_LIBS ON)
set(CMAKE_FIND_LIBRARY_SUFFIXES .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
set(LINK_SEARCH_START_STATIC TRUE)
set(LINK_SEARCH_END_STATIC TRUE)
set(SHARED_LIBS OFF)
set(STATIC_LIBS ON)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static")
Using these, CMake attempts to build every program statically (as expected) - however, it fails because I don't have Xaw.a - I can't find out whether this actually should exist. I have installed the latest libxaw7-dev which I was expecting to fix it. One option would be to compile the X11 libraries myself, but I don't really want to do that...
if I comment out only set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static"), then CMake compiles everything, but uses shared libraries for every program, even though I specify the location of .a X11 libraries in my find_library() calls. I was expecting CMake to use the .a files where it could and then only use shared libraries - is there a way to force this behaviour?
does anyone know yet of a fix for the bug described here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46539; whereby gfortran seemingly can't statically link libquadmath? I tried the fix using gcc but I can't get CMake to recognise the libgfortran flag:
cmake -DCMAKE_Fortran_COMPILER=gcc -DCMAKE_Fortran_FLAGS=-gfortran
results in
-- The Fortran compiler identification is unknown
-- Check for working Fortran compiler: /usr/bin/gcc
-- Check for working Fortran compiler: /usr/bin/gcc -- broken
CMake Error at /usr/share/cmake-2.8/Modules/CMakeTestFortranCompiler.cmake:54 (message):
The Fortran compiler "/usr/bin/gcc" is not able to compile a simple test program.
However, as you might have noticed, I set the location of the libquadmath.a; when I build a program which doesn't use X11 but does use quadmath when I use
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static")
then the program does compile successfully (running ldd reports 'not a dynamic executable') - does this mean that the bug has been fixed, or does it only work because I set the location in CMake?
I was having a similar problem. Turns out that cmake was implicitly linking against libgfortran and libquadmath. To fix this I put the following in my top level CMakeLists.txt:
unset(CMAKE_Fortran_IMPLICIT_LINK_LIBRARIES)
I could then explicitly link again the libraries using:
SET_TARGET_PROPERTIES(main_f PROPERTIES LINKER_LANGUAGE "C"
LINK_FLAGS
"/usr/local/Cellar/gcc/7.1.0/lib/gcc/7/libgfortran.a
/usr/local/Cellar/gcc/7.1.0/lib/gcc/7/libquadmath.a -lm -lgcc"
)
The static version of libgfortran is necessary because the shared library also depends on libquadmath. The added "-lm" and "-lgcc" bring in the system dynamic versions of these libraries. On a mac system, you would want to use the full path to your libm.a as well.
I guess your questions are not that much related, I don't know the answer for all of them.
For your static linking problems, since you're using GCC, you can pass multiple -static and -dynamic flags to it:
set(CMAKE_EXE_LINKER_FLAGS "-static ${STATIC_LIBS} -dynamic ${EVERYTHING ELSE} -static ${MORE_STATIC_LIBS}")
I don't know why Xaw.a isn't available on your system, probably because the package maintainer of your Linux distribution didn't really make them available.
Also, compiling everything static might make things not compatible between all distros out there and you cripple the ability for others to use improved, up-to-date libraries with your program, it might not be what you want.
If you intend to make a self-contained package of your program, it might be better just to include the shared libraries you used together, like Dropbox and many other proprietary applications do (Humble Bundle games are other example).