Using cmake to cross compile multiple libraries and apps - c

Question

I'm having issues with cmake while trying to cross compile an existing, large codebase. Our current build system uses a proprietary IDE that is causing a large number of issues -- so we're trying to move away.
I've distilled this to the simplest example I can.
Note: This all works when I don't use the toolchain option with cmake. I can get this to compile and run if just using the native toolchain.
I don't currently suspect issues with the toolchain file for cmake. I have used it to get OpenCV to compile -- with some hacking OpenCV.
The error that I get when trying to cross compile is:
-- The C compiler identification is GNU 4.8.3
-- The CXX compiler identification is GNU 4.8.3
-- Check for working C compiler: /opt/qnx650/host/linux/x86/usr/bin/ntox86-gcc
-- Check for working C compiler: /opt/qnx650/host/linux/x86/usr/bin/ntox86-gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /opt/qnx650/host/linux/x86/usr/bin/ntox86-g++
-- Check for working CXX compiler: /opt/qnx650/host/linux/x86/usr/bin/ntox86-g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/MY_USER/Desktop/test_app/build-test_app
Scanning dependencies of target liba
[ 25%] Building C object libs/liba/CMakeFiles/liba.dir/liba.c.o
Linking C shared library libliba.so
[ 25%] Built target liba
Scanning dependencies of target libb
[ 50%] Building C object libs/libb/CMakeFiles/libb.dir/libb.c.o
make[2]: *** No rule to make target `libs/liba/liba.a', needed by `libs/libb/liblibb.so.1.0.0'. Stop.
make[1]: *** [libs/libb/CMakeFiles/libb.dir/all] Error 2
make: *** [all] Error 2
It's like it's looking for a static version of the library, but I've configured it to use shared objects when calling cmake:
cmake -DBUILD_SHARED_LIBS=1 ..
I've included all of the files in the test project below. This is the same issue I run into when trying to get the larger project to compile.
Project structure:
test_app
├── app
│   ├── appa
│   │   ├── appa.c
│   │   └── CMakeLists.txt
│   └── CMakeLists.txt
├── CMakeLists.txt
├── include
│   ├── liba
│   │   └── liba.h
│   ├── libb
│   │   └── libb.h
│   └── libc
│   └── libc.h
└── libs
├── CMakeLists.txt
├── liba
│   ├── CMakeLists.txt
│   └── liba.c
├── libb
│   ├── CMakeLists.txt
│   └── libb.c
└── libc
├── CMakeLists.txt
└── libc.c
Top level CMakeLists.txt
project(test)
cmake_minimum_required(VERSION 2.8)
set(CMAKE_INSTALL_PREFIX "/opt/test")
set(INSTALL_PERMISSIONS OWNER_READ OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_EXECUTE)
set(TEST_VERSION 1.0.0)
set(TEST_MAJOR_VERSION 1)
set(TEST_GLOBAL_INCLUDES
$<BUILD_INTERFACE:${CROSS_TARGET}/usr/pkg/include>
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
)
set(TEST_GLOBAL_LIB_PATHS
$<BUILD_INTERFACE:${CROSS_TARGET}/usr/pkg/include>
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
)
add_subdirectory(libs)
add_subdirectory(app)
app/CMakeLists.txt
add_subdirectory(appa)
app/appa/CMakeLists.txt
project(appa)
add_executable(appa appa.c)
target_include_directories(appa PUBLIC ${TEST_GLOBAL_INCLUDES})
target_link_libraries(appa libc)
# Set version information
set_target_properties(appa PROPERTIES
VERSION ${TEST_VERSION}
)
# set install destination and permissions
install(
TARGETS appa
RUNTIME DESTINATION lib
PERMISSIONS ${INSTALL_PERMISSIONS}
)
app/appa/appa.c
#include <stdlib.h>
#include <stdio.h>
#include <libc/libc.h>
int main(int argc, char **argv)
{
printf("Hello world: %d\n", libc_function(2));
return EXIT_SUCCESS;
}
include/liba/liba.h
#pragma once
int liba_function(int a);
include/libb/libb.h
#pragma once
int libb_function(int a);
include/libc/libc.h
#pragma once
int libc_function(int a);
libs/CMakeLists.txt
add_subdirectory(liba)
add_subdirectory(libb)
add_subdirectory(libc)
libs/liba/CMakeLists.txt
project(libliba)
add_library(liba liba.c)
target_include_directories(liba PUBLIC ${TEST_GLOBAL_INCLUDES})
# Set version information
set_target_properties(liba PROPERTIES
VERSION ${TEST_VERSION}
SOVERSION ${TEST_MAJOR_VERSION}
)
# set install destination and permissions
install(
TARGETS liba
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib
RUNTIME DESTINATION lib
PERMISSIONS ${INSTALL_PERMISSIONS}
)
libs/liba/liba.c
#include <liba/liba.h>
int liba_function(int a)
{
return a * a;
}
libs/libb/CMakeLists.txt
project(liblibb)
add_library(libb libb.c)
target_include_directories(liba PUBLIC ${TEST_GLOBAL_INCLUDES})
# Set version information
set_target_properties(libb PROPERTIES
VERSION ${TEST_VERSION}
SOVERSION ${TEST_MAJOR_VERSION}
)
target_link_libraries(libb liba)
# set install destination and permissions
install(
TARGETS libb
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib
RUNTIME DESTINATION lib
PERMISSIONS ${INSTALL_PERMISSIONS}
)
libs/libb/libb.c
#include <liba/liba.h>
#include <libb/libb.h>
int libb_function(int a)
{
return liba_function(a) * liba_function(a);
}
libs/libc/CMakeLists.txt
project(liblibc)
add_library(libc libc.c)
target_include_directories(libc PUBLIC ${TEST_GLOBAL_INCLUDES})
# Set version information
set_target_properties(libc PROPERTIES
VERSION ${TEST_VERSION}
SOVERSION ${TEST_MAJOR_VERSION}
)
target_link_libraries(libc libb)
# set install destination and permissions
install(
TARGETS libc
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib
RUNTIME DESTINATION lib
PERMISSIONS ${INSTALL_PERMISSIONS}
)
libs/libc/libc.c
#include <libb/libb.h>
#include <libc/libc.h>
int libc_function(int a)
{
return libb_function(a) * libb_function(a);
}