I am using the arm-linux-androideabi-g++
compiler. When I try to compile a simple "Hello, World!" program it compiles fine. When I test it by adding a simple exception handling in that code it works too (after adding -fexceptions
.. I guess it is disabled by default).
This is for an Android device, and I only want to use CMake, not ndk-build
.
For example - first.cpp
#include <iostream>
using namespace std;
int main()
{
try
{
}
catch (...)
{
}
return 0;
}
./arm-linux-androideadi-g++ -o first-test first.cpp -fexceptions
It works with no problem...
The problem ... I am trying to compile the file with a CMake file.
I want to add the -fexceptions
as a flag. I tried with
set (CMAKE_EXE_LINKER_FLAGS -fexceptions ) or set (CMAKE_EXE_LINKER_FLAGS "fexceptions" )
and
set ( CMAKE_C_FLAGS "fexceptions")
It still displays an error.
Try setting the variable CMAKE_CXX_FLAGS
instead of CMAKE_C_FLAGS
:
set (CMAKE_CXX_FLAGS "-fexceptions")
The variable CMAKE_C_FLAGS
only affects the C compiler, but you are compiling C++ code.
Adding the flag to CMAKE_EXE_LINKER_FLAGS
is redundant.
In newer versions of CMake you can set compiler and linker flags for a single target with target_compile_options
and target_link_libraries
respectively (yes, the latter sets linker options too):
target_compile_options(first-test PRIVATE -fexceptions)
The advantage of this method is that you can control propagation of options to other targets that depend on this one via PUBLIC
and PRIVATE
.
As of CMake 3.13 you can also use target_link_options
to add linker options which makes the intent more clear.
The preferred way to specify toolchain-specific options is using CMake's toolchain facility. This ensures that there is a clean division between:
Ideally, there should be no compiler/linker flags in your CMakeLists.txt files -- even within if
/endif
blocks. And your program should build for the native platform with the default toolchain (e.g. GCC on GNU/Linux or MSVC on Windows) without any additional flags.
Steps to add a toolchain:
Create a file, e.g. arm-linux-androideadi-gcc.cmake with global toolchain settings:
set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++)
set(CMAKE_CXX_FLAGS_INIT "-fexceptions")
(You can find an example Linux cross-compiling toolchain file here.)
When you want to generate a build system with this toolchain, specify the CMAKE_TOOLCHAIN_FILE
parameter on the command line:
mkdir android-arm-build && cd android-arm-build
cmake -DCMAKE_TOOLCHAIN_FILE=$(pwd)/../arm-linux-androideadi-gcc.cmake ..
(Note: you cannot use a relative path.)
Build as normal:
cmake --build .
Toolchain files make cross-compilation easier, but they have other uses:
Hardened diagnostics for your unit tests.
set(CMAKE_CXX_FLAGS_INIT "-Werror -Wall -Wextra -Wpedantic")
Tricky-to-configure development tools.
# toolchain file for use with gcov
set(CMAKE_CXX_FLAGS_INIT "--coverage -fno-exceptions -g")
Enhanced safety checks.
# toolchain file for use with gdb
set(CMAKE_CXX_FLAGS_DEBUG_INIT "-fsanitize=address,undefined -fsanitize-undefined-trap-on-error")
set(CMAKE_EXE_LINKER_FLAGS_INIT "-fsanitize=address,undefined -static-libasan")
You can also add linker flags to a specific target using the LINK_FLAGS
property:
set_property(TARGET ${target} APPEND_STRING PROPERTY LINK_FLAGS " ${flag}")
If you want to propagate this change to other targets, you can create a dummy target to link to.
Source: Stackoverflow.com