I inherited a C++ code with a dependency to OpenMPI that I want to delegate to Conan and CMake, and the automated build has a strange (to me at least) behavior related to sysctl that I want to understand.
How I tried to do it
I declared the required dependencies in my root CMakeLists.txt:
Note: I added the full list of requirements because I also suspect that some of them may be in conflict? That happened before with boost, that forced me to set explicitly zlib (if i remember correctly).
# stuff ...
conan_cmake_configure(
REQUIRES
zlib/1.2.12
mp-units/0.7.0
boost/1.79.0
openmpi/4.1.0
gsl/2.7
cspice/0067
GENERATORS
cmake
# that is required for cspice
CMakeDeps
CMakeToolchain
)
# more stuff ...
and then in the application CmakeLists.txt I find, include and link the executable to the required libraries:
add_executable(spock main.cpp)
find_package(cspice REQUIRED)
find_package(openmpi REQUIRED)
target_include_directories(
spock PRIVATE $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>
openmpi_INCLUDE_DIRS
cspice_INCLUDE_DIRS
)
target_link_libraries(spock
CONAN_PKG::boost
CONAN_PKG::mp-units
openmpi::openmpi
cspice::cspice
)
# We need C++ 20 activated with the concepts library
target_compile_features(spock PUBLIC cxx_std_20)
Problem: undefined reference to sysctl ... on my local system only.
Building on my local machine with CMake 3.23.2 results in the following error message:
Consolidate compiler generated dependencies of target spock
[ 25%] Building CXX object src/CMakeFiles/spock.dir/main.cpp.o
^[[A^[[A[ 50%] Linking CXX executable ../bin/spock
/usr/bin/ld: /home/becheler/.conan/data/openmpi/4.1.0/_/_/package/8f7048d1bf6fc2a7985eb087c34e69a5e64f6c86/lib/libopen-pal.a(evutil_rand.o): in function `arc4_stir.isra.0':
evutil_rand.c:(.text+0x3d2): undefined reference to `sysctl'
collect2: error: ld returned 1 exit status
gmake[2]: *** [src/CMakeFiles/spock.dir/build.make:146: bin/spock] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:135: src/CMakeFiles/spock.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2
However, the same build on Github workflows on Ubuntu 20.04 works. What is weird. The only difference before apart the distribution version is that github wokflows use higher privileges than me on local (I believe?).
What I tried so far
I've been trying to read about what this sysctlreference is. And I found conflicting information:
Frrom this man page:
The sysctl() function retrieves system information and allows processes with appropriate privileges to set system information.
this similar SO question came to the conclusion that
Linux does not support this function (other OS like MacOS or FreeBSD support it)
A comment from the same post concludes that in Linux,
these details can be obtained by reading the kernel-provided
pseudofiles /proc/cpuinfo and /proc/meminfo
So here is my question: why does it compile at all on the remote server if this command is not supposed to exist on the OS used?
Related
while I am building glibc library using yocto project it is giving
error: missing attribute ((constructor)) support??
after adding the coverage flags:
TARGET_CFLAGS += "-fprofile-arcs -ftest-coverage"
TARGET_LDFLAGS += "-lgcov -fprofile-arcs -ftest-coverage"
still, I am getting an error for glibc.
Please find the link of config log file : https://drive.google.com/file/d/14tiQJ8JIFE_tDWt3H9tS8zBBQROcZDNa/view
It is not working even after adding the following line in conf/local.conf :
EXTRA_OECONF = "libc_cv_ctors_header=yes"
Even i tried this
EXTRA_OECONF_append = "libc_cv_ctors_header=yes"
please find the config log file generated during compilation : https://drive.google.com/open?id=1kxTu8pt7h_9ty55OywP9Ilmmp04T61Rr
So, How to resolve this error?
Log file error Point
poky-linux/gcc/i586-poky-linux/8.2.0/ld: /tmp/ccxetEc1.o: in function `_GLOBAL__sub_D_00100_1__start':
conftest.c:(.text.exit+0x40): undefined reference to `__gcov_exit'<br>
collect2: error: ld returned 1 exit status<br>
configure:5682: $? = 1<br>
configure:5702: error: missing __attribute__ ((constructor)) support??
You are trying to build glibc with -fprofile-arcs -ftest-coverage in CFLAGS. That will not work. The errors you see are a result of these incorrect compiler flags.
A profiling glibc requires fairly substantial changes throughout the library and needs to be created by building with --enable-profile (which is not the default).
I had this error while I tried to enable coverage on a C project using a C++ test harness (CppUTest). Build system was handled by CMake.
Compilers and gcov were aligned on the same version (gcc --version, g++ --version and gcov --version gave the same version) but it seems that my build system was generated with a gcc 5 (resulting to an additional included directory by the linker: usr/lib/gcc/x86_64-linux-gnu/5). I clean the build tree and generated it again thanks to CMake which fixed the error.
I'm trying to make a shared library, in Linux, which is a *.so. My DMD version is 2, latest. I'm just trying yo compile a simple empty shared library, with the code that Mono-D(plugin for MonoDevelop) creates. When I try to compile it, it tells me to check the build log, this is what's in the build log:
Building Solution: QScr (Debug)
Building: QScr (Debug)
Performing main compilation...
Current dictionary: /home/nafees/Desktop/Projects/QScr/QScr
dmd -debug -gc "myclass.d" "dllmain.d" "-I/usr/include/dmd" "-L/IMPLIB:/home/nafees/Desktop/Projects/QScr/QScr/bin/Debug/libQScr.a" "-odobj/Debug" "-of/home/nafees/Desktop/Projects/QScr/QScr/bin/Debug/libQScr.so" -w -vcolumns
/usr/bin/ld: cannot find /IMPLIB:/home/nafees/Desktop/Projects/QScr/QScr/bin/Debug/libQScr.a: No such file or directory
collect2: error: ld returned 1 exit status
--- errorlevel 1
Exit code 1
Build complete -- 1 error, 0 warnings
---------------------- Done ----------------------
Build: 1 error, 0 warnings
This is what dllmain contains:
module dllmain;
And in myclass.d:
module myclass;
class MyClass
{
//TODO: Enter class code here
}
export:
extern(D):
MyClass createMyClass()
{
return new MyClass();
}
I have no idea what is that a file, I'm still fairly new to D, and Linux.
How do I get it to compile? And could someone explain to me what is an .a file?
EDIT: No, it's not a duplicate, I'm trying to compile, while that question is about loading libraries.
EDIT2: I checked the directory, the .a file doesn't exist.
/usr/bin/ld: cannot find /IMPLIB:/home/nafees/Desktop/Projects/QScr/QScr/bin/Debug/libQScr.a: No such file or directory
/IMPLIB is a Windows linker switch. Your IDE is misconfigured (or just buggy).
Try changing the project settings in the IDE or filing a bug against the IDE.
Few things.
extern(D) would not be needed for free functions since it is default
You don't need createMyClass function at all, new will work fine
-shared must be passed to dmd for it to create a shared library
In case you didn't know, you will be passing the files in the shared library as import files when compiling the host binary.
For one of my Qt Embedded projects I'm using a external Qt lib called SMTPEmail. This lib needs to be compiled before being included into a project, something that I managed to do successfully both for Qt 4.8 ARM and for Desktop.
The problem I'm getting is that when I include the headers into my project and include the library in the .pro, the linker gives me
(path_to_libs)/libSMTPEmail.so: undefined reference to `QSslSocket::connectToHostEncrypted(QString const&, unsigned short, QFlags<QIODevice::OpenModeFlag>)'
(path_to_libs)/libSMTPEmail.so: undefined reference to `QSslSocket::QSslSocket(QObject*)'
collect2: ld returned 1 exit status
make: *** [re8k_interface-tgt] Error 1
but only for compiling for ARM. IOW compiling the lib for both ARM and Desktop goes OK, compiling the project for Desktop using the lib goes OK but compiling it for ARM using the lib goes wrong.
Following this forum thread I suspected this could be due to missing the link to the library file of openssl (the project points to different lib folders when compiling for different environments). So I searched for all "openssl" related files inside the compiler for ARM (arm-arago-linux-gnueabi) and included in the same folder where the .so is located; same error. I then suspected the lib itself had other dependencies which were not in the path_to_libs, so I did a readelf -d libSMTPEmail.so and later in the .so.1 and readelf did return some lib dependencies that were not inside the same folder of the library. I then copied all such dependencies to the folder and got no success either.
So what could be happening? All dependencies known by me were put in place and I still get the error only for the situation where the lib is included by another project compiled for ARM.
You need to point your QMake where your libs and header file is in your .pro file;
So find where your library is assume /usr/local/include then ;
INCLUDEPATH += /usr/local/include
Add which libs you will use;
LIBS += -lSMTPEmail
You can check my answer here;
Two things stand out for me in your question:
1.
undefined reference to
This error message means that there was an error in the linking step of compilation. This occurs when you include a header to a function/class/variable but don't have the definition included in your own sources, or you do not link in a static library that does.
Searching for dependencies in libraries that are already compiled (.dll or .so) is too late, the compiler is looking for a static link, not a dynamic link.
2.
compiling the lib for both ARM and Desktop goes OK, compiling the
project for Desktop using the lib goes OK but compiling it for ARM
using the lib goes wrong.
This suggests that you are using conditional compilation in your .pro file that does a "both" compilation, a "desktop only" compilation and a "ARM only" compilation. If this is correct, you need to examine your compilation instructions for your "ARM only" compilation.
The error message itself refers to you using two functions from the QSslStock class. These are part of the QtNetwork module so you should have the following in your .pro file in order for the necessary links to be formed.
Qt += network
I am trying to compile QT 5.5.1 on Amazon AMI 2015.09, which looks la lot like Centos 6.5.
I keep getting this error:
Project ERROR: Unknown module(s) in QT: quick
However, there is no quick module that I can find, and no obvious way to enable to disable it from looking at the ./configure script.
My procedure:
I downloaded qt-everywhere-opensource-src-5.5.1.tar.gz
I unpacked it.
I ran ./configure
Confirmed that I want the opensource license and agreed to the LGPL.
Ran gmake -j4 (but I get the same behavior with gmake.
Interestingly, make distclean gives me this error:
Project ERROR: Unknown module(s) in QT: quick-private
Here are all of the errors sent to STDERR:
Checking for openal... Checking for bluez... no
Checking for bluez_le... no
Checking for btapi10_2_1... no
/home/ec2-user/qt-everywhere-opensource-src-5.5.1/qtmultimedia/qtmultimedia.pro:28: Variable GST_VERSION is not defined.
Checking for resourcepolicy... no
Checking for gpu_vivante... no
Checking for libbb2... no
no
Project MESSAGE: Unsupported Bluetooth platform, will not build a working QtBluetooth library.
Project MESSAGE: Either no Qt D-Bus found or no BlueZ headers.
qbluetoothdevicediscoveryagent_p.h:0: Note: No relevant classes found. No output generated.
qbluetoothservicediscoveryagent_p.h:0: Note: No relevant classes found. No output generated.
qbluetoothserver_p.h:0: Note: No relevant classes found. No output generated.
qbluetoothlocaldevice_p.h:0: Note: No relevant classes found. No output generated.
Checking for assimp... no
Project ERROR: Unknown module(s) in QT: quick
gmake[4]: *** [sub-textureandlight-make_first] Error 3
gmake[3]: *** [sub-canvas3d-make_first] Error 2
gmake[2]: *** [sub-canvas3d-make_first] Error 2
gmake[1]: *** [sub-examples-make_first] Error 2
gmake: *** [module-qtcanvas3d-make_first] Error 2
gmake: *** Waiting for unfinished jobs....
At another poster's suggestion I tried ./configure -skip qtquick but that didn't work:
$ ./configure -skip qtquick
+ cd qtbase
+ /home/ec2-user/qt-everywhere-opensource-src-5.5.1/qtbase/configure -top-level -skip qtquick
Attempting to skip non-existent module qtquick.
$
this is what I think will solve your problems:
You have use `make confclean' instead of making distclean for deleting the previous configuration.
Configure in verbose mode — more information will be provided, sorry, I don't remember exact flag, if I'm not mistaken, it's -v.
If you don't need quick, add -skip qtquick to the configure.
I was trying to compile libSDL-1.2.14 for my mips platform.
But it was not successful.
These were the steps that I tried out :
export PATH=/opt/mips-4.3/bin:$PATH
Went inside the libSDL-1.2.14 source folder.
Gave a "./configure --prefix=/usr/local/SDL_Lib --host=mips-linux-gnu"
Executed the "make" command
This was the error received :
cc1: warning: include location
"/usr/include" is unsafe for
cross-compilation
./src/audio/dma/SDL_dmaaudio.c: In
function 'DMA_WaitAudio':
./src/audio/dma/SDL_dmaaudio.c:167:
error: can't find a register in class
'COP3_REGS' while reloading 'asm'
./src/audio/dma/SDL_dmaaudio.c:167:
error: 'asm' operand has impossible
constraints make: *
[build/SDL_dmaaudio.lo] Error 1
But then i reconfigured the make file by giving the following commands :
make clean
./configure --prefix=/usr/local/SDL_Lib --host=mips-linux-gnu CPPFLAGS=-I/opt/mips-4.3/mips-linux-gnu/libc/usr/include/
make
NOTE : /opt/mips-4.3/mips-linux-gnu/libc/usr/include/ - This is the path where you can locate the select.h file for the mips Platform.
It contains the definitions of the macros FD_ZERO and FD_SET.
Still I am getting the same error.
cc1: warning: include location
"/usr/include" is unsafe for
cross-compilation
./src/audio/dma/SDL_dmaaudio.c: In
function 'DMA_WaitAudio':
./src/audio/dma/SDL_dmaaudio.c:167:
error: can't find a register in class
'COP3_REGS' while reloading 'asm'
./src/audio/dma/SDL_dmaaudio.c:167:
error: 'asm' operand has impossible
constraints make: *
[build/SDL_dmaaudio.lo] Error 1
Please help me with some valuable pointers.
Thanks,
Sen
First, don't set the path to the cross-compiler as the first part of your PATH, set it as last:
export PATH=$PATH:<path to cross-compiler>
It's safer this way. Second, run ./configure --help to get all the options. What that error message would say if it was smarter is the following:
You're trying to cross-compile since you're setting the --host flag
But you're not changing any of the other options for where to find includes and libs for the target environment
I'm going to use /usr/include by default
But that's for the host system which will not work when cross-compiling
Check what other configure options you need to set to tell the configure script where to find the .h files (includes) and the libraries for your target. These usually come with the cross-compiler that you download. Also, you should probably set the CROSS_COMPILE environment variable to the cross-compiler prefix before running configure. The prefix is the part before gcc in a cross-compiler, assuming you're using GCC as your cross-compiler.