Disable run test for pthread detection.
In case of build with only static library, CMake fails to detect the
pthread library (-lpthread), so it falls back trying to link using
-pthread and execute the test program.
<snip>
[...]
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - not found
-- Check if compiler accepts -pthread
CMake Error: TRY_RUN() invoked in cross-compiling mode, please set the following cache variables appropriately:
THREADS_PTHREAD_ARG (advanced)
For details see /home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/TryRunResults.cmake
-- Check if compiler accepts -pthread - no
-- Found Threads: TRUE
-- Udev rules not being installed, install them with -DINSTALL_UDEV_RULES=ON
-- Building with kernel driver detaching disabled, use -DDETACH_KERNEL_DRIVER=ON to enable
-- Building for version: 0.5.3 / 0.5.3
-- Using install prefix: /usr
-- Configuring incomplete, errors occurred!
See also "/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeOutput.log".
See also "/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeError.log".
</snip>
Here it fails because, in the CMake FindThreads.cmake file, the
'try_run' function is unconditionally called [1].
Also, the CMakeError.log gives more details why linking with -lpthread
fails:
<snip>
[...]
Run Build Command:"/usr/bin/make" "cmTryCompileExec3012181287/fast"
make[1]: Entering directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTryCompileExec3012181287.dir/build.make CMakeFiles/cmTryCompileExec3012181287.dir/build
make[2]: Entering directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
/home/buildroot/instance-1/output/host/usr/bin/cmake -E cmake_progress_report /home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec3012181287.dir/CheckFunctionExists.c.o
/home/buildroot/instance-1/output/host/usr/bin/arm-linux-gcc -pipe -Os -static -DCHECK_FUNCTION_EXISTS=pthread_create -o CMakeFiles/cmTryCompileExec3012181287.dir/CheckFunctionExists.c.o -c /home/buildroot/instance-1/output/host/usr/share/cmake-3.0/Modules/CheckFunctionExists.c
Linking C executable cmTryCompileExec3012181287
/home/buildroot/instance-1/output/host/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec3012181287.dir/link.txt --verbose=1
/home/buildroot/instance-1/output/host/usr/bin/arm-linux-gcc -pipe -Os -static -DCHECK_FUNCTION_EXISTS=pthread_create -static CMakeFiles/cmTryCompileExec3012181287.dir/CheckFunctionExists.c.o -o cmTryCompileExec3012181287 -rdynamic -lpthread -Wl,-Bstatic -lusb-1.0 -Wl,-Bdynamic
/home/buildroot/instance-1/output/host/usr/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libpthread.a(init.os): In function `__pthread_initialize_minimal':
init.c:(.text+0x270): undefined reference to `__libc_setup_tls'
collect2: error: ld returned 1 exit status
CMakeFiles/cmTryCompileExec3012181287.dir/build.make:89: recipe for target 'cmTryCompileExec3012181287' failed
make[2]: *** [cmTryCompileExec3012181287] Error 1
make[2]: Leaving directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
Makefile:118: recipe for target 'cmTryCompileExec3012181287/fast' failed
make[1]: *** [cmTryCompileExec3012181287/fast] Error 2
make[1]: Leaving directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
Determining if compiler accepts -pthread returned PLEASE_FILL_OUT-FAILED_TO_RUN instead of 2. The compiler had the following output:
Change Dir: /home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make" "cmTryCompileExec1361818630/fast"
make[1]: Entering directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTryCompileExec1361818630.dir/build.make CMakeFiles/cmTryCompileExec1361818630.dir/build
make[2]: Entering directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
/home/buildroot/instance-1/output/host/usr/bin/cmake -E cmake_progress_report /home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec1361818630.dir/CheckForPthreads.c.o
/home/buildroot/instance-1/output/host/usr/bin/arm-linux-gcc -pipe -Os -static -o CMakeFiles/cmTryCompileExec1361818630.dir/CheckForPthreads.c.o -c /home/buildroot/instance-1/output/host/usr/share/cmake-3.0/Modules/CheckForPthreads.c
Linking C executable cmTryCompileExec1361818630
/home/buildroot/instance-1/output/host/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec1361818630.dir/link.txt --verbose=1
/home/buildroot/instance-1/output/host/usr/bin/arm-linux-gcc -pipe -Os -static -static CMakeFiles/cmTryCompileExec1361818630.dir/CheckForPthreads.c.o -o cmTryCompileExec1361818630 -rdynamic -pthread
make[2]: Leaving directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
make[1]: Leaving directory '/home/buildroot/instance-1/output/build/librtlsdr-v0.5.3/CMakeFiles/CMakeTmp'
</snip>
While falling back on -pthread is correct when using only static
libraries to get some tls-related macros defined [2,3], it is wrong to
try to run the test program in case of cross-compilation.
So, this patch only disable run test when pthread support is done using
-pthread, i.e. in case of the type of libraries is "static only".
Fixes:
http://autobuild.buildroot.org/results/26c/26cb8c2e5f867d49451f61304bf0a1a6f7b825d9/
[1] http://www.cmake.org/gitweb?p=cmake.git;a=blob;f=Modules/FindThreads.cmake;h=a0bc4d133eb3f9d3ae096f0e03e419ef7be66ce8;hb=HEAD#l84
[2] http://lists.busybox.net/pipermail/buildroot/2014-June/100690.html
[3] http://stackoverflow.com/questions/23250863/difference-between-pthread-and-lpthread-while-compiling
Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
4c6eace6f7