cmake 不会使用 pthreads 构建 Linux c++11 交叉编译程序答案

【问题标题】：cmake won't build a Linux c++11 cross-compiled program with pthreadscmake 不会使用 pthreads 构建 Linux c++11 交叉编译程序
【发布时间】：2016-05-31 08:11:43
【问题描述】：

简而言之，我可以使用直接的 g++ 命令行来构建程序。它构建然后在目标上成功执行。

但是，如果我使用我能想到的最简单的 cmake 脚本，则构建成功，但程序无法在目标上执行。可执行文件的失败输出是：

terminate called after throwing an instance of 'std::system_error'
what():  Enable multithreading to use std::thread: Operation not permitted
Aborted

我用于成功构建和执行的 g++ 命令行是：

/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++ -o ThreadTest -std=c++11 -pthread main.cpp ThreadTest.cpp

当我在目标上运行直接的 g++ 程序时，我得到：

Atomic Success Count: 1000 of 1000.

Mutex Success Count: 1000 of 1000.

Unclean Success Count: 922 of 1000.
Unclean Failure Count: 78 of 1000.

我使用的 CMakeLists.txt 文件是：

# cmake file for building the ThreadTest executable.  This requires c++11.
CMAKE_MINIMUM_REQUIRED(VERSION 2.8.12)

# !!! Set up the compiler to use, first (i.e. before the PROJECT() call.)
# gcc location.
SET(CROSS_COMPILE_FULL
   "/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-")
# sysroot location
SET(CROSS_COMPILE_FULL_HOST
   "/opt/criticallink/mityomapl138_20151114/sysroots/arm926ejste-criticallink-linux-gnueabi")
SET(CMAKE_C_COMPILER "${CROSS_COMPILE_FULL}gcc")
SET(CMAKE_CXX_COMPILER "${CROSS_COMPILE_FULL}g++")
SET(CMAKE_FIND_ROOT_PATH "${CROSS_COMPILE_FULL_HOST}")
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

# The project will use the compiler specified above (or the default compiler for Windows.)
PROJECT(CommonSDK)

SET(MY_TEST_HOME "$ENV{TEST_HOME}")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pthread")

SET(CUR_PROJECT_NAME ThreadTest)
SET(PROJECT_HOME_DIR "${MY_TEST_HOME}/${CUR_PROJECT_NAME}")
SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY "$ENV{TEST_EXEC_HOME}")

FILE(GLOB CUR_PROJECT_FILES "${PROJECT_HOME_DIR}/*.cpp" "${PROJECT_HOME_DIR}/*.h")

FIND_PACKAGE(Threads REQUIRED)
ADD_EXECUTABLE(${CUR_PROJECT_NAME} ${CUR_PROJECT_FILES})
TARGET_LINK_LIBRARIES(${CUR_PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})

我通过以下方式调用 cmake：

mkdir build
cd build
cmake ..

cmake 的输出是：

-- The C compiler identification is GNU 4.8.3
-- The CXX compiler identification is GNU 4.8.3
-- Check for working C compiler: /opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-gcc
-- Check for working C compiler: /opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++
-- Check for working CXX compiler: /opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not 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 - found
-- Found Threads: TRUE  
-- Configuring done
-- Generating done
-- Build files have been written to: /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build

这是来自 make 的 VERBOSE 输出：

make VERBOSE=1

/usr/bin/cmake -H/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest -B/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/cmake -E cmake_progress_start /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/progress.marks
make -f CMakeFiles/Makefile2 all
make[1]: Entering directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
make -f CMakeFiles/ThreadTest.dir/build.make CMakeFiles/ThreadTest.dir/depend
make[2]: Entering directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
cd /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/ThreadTest.dir/DependInfo.cmake --color=
Dependee "/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/ThreadTest.dir/DependInfo.cmake" is newer than depender "/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/ThreadTest.dir/depend.internal".
Dependee "/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/CMakeDirectoryInformation.cmake" is newer than depender "/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles/ThreadTest.dir/depend.internal".
Scanning dependencies of target ThreadTest
make[2]: Leaving directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
make -f CMakeFiles/ThreadTest.dir/build.make CMakeFiles/ThreadTest.dir/build
make[2]: Entering directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
/usr/bin/cmake -E cmake_progress_report /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles 1
[ 50%] Building CXX object CMakeFiles/ThreadTest.dir/main.cpp.o
/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++    -O2 -pipe -g -feliminate-unused-debug-types  -std=c++11 -pthread   -o CMakeFiles/ThreadTest.dir/main.cpp.o -c /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/main.cpp
/usr/bin/cmake -E cmake_progress_report /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles 2
[100%] Building CXX object CMakeFiles/ThreadTest.dir/ThreadTest.cpp.o
/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++    -O2 -pipe -g -feliminate-unused-debug-types  -std=c++11 -pthread   -o CMakeFiles/ThreadTest.dir/ThreadTest.cpp.o -c /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/ThreadTest.cpp
Linking CXX executable /home/mitydsp/Code/CommonSDK/OutputTest/DbricHost/ThreadTest
/usr/bin/cmake -E cmake_link_script CMakeFiles/ThreadTest.dir/link.txt --verbose=1
/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-g++    -O2 -pipe -g -feliminate-unused-debug-types  -std=c++11 -pthread   -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed CMakeFiles/ThreadTest.dir/main.cpp.o CMakeFiles/ThreadTest.dir/ThreadTest.cpp.o  -o /home/mitydsp/Code/CommonSDK/OutputTest/DbricHost/ThreadTest -rdynamic -lpthread 
make[2]: Leaving directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
/usr/bin/cmake -E cmake_progress_report /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles  1 2
[100%] Built target ThreadTest
make[1]: Leaving directory `/home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build'
/usr/bin/cmake -E cmake_progress_start /home/mitydsp/Code/CommonSDK/source/Tests/ThreadTest/build/CMakeFiles 0

我已经详尽地查看了 StackOverflow、Google 等。我遇到的建议已包含在上面的 CMakeLists.txt 中。但我仍然无法让 cmake 可执行文件在目标上正常运行。

任何帮助将不胜感激！

【问题讨论】：

我不知道答案，但您可能希望包含运行 make VERBOSE=1 时的输出。也许您正在链接不同的线程库。
我想知道它是否也链接到不同的线程库。特别是因为 cmake 期间的 pthread_create - not found 实例。我无法从FIND_PACKAGE(Threads) 调用中找到任何指示它找到pthreads 库的where 的cmake 变量。我的构建系统有原生 x86_64 编译器和两个 arm 交叉编译器——每个都有自己的 sysroot。
@f1fan44，这意味着在未使用 libpthread 时未找到 pthread_create。第三个测试显示它是通过正确的库找到的，因此 cmake 将使用该库。或者应该做。 ldd ThreadTest 显示什么？它是否链接到 libpthread.so ？
程序成功时ldd显示：libpthread.so.0 => lib/libpthread.so.0 (0x428d0000)失败时ldd根本没有libpthread。

标签： linux c++11 cmake pthreads cross-compiling

【解决方案1】：

我可以通过添加-Wl,--no-as-needed 链接器选项来解决这个问题。在 CMakeLists.txt 文件中，它是这样完成的：

SET(CMAKE_EXE_LINKER_FLAGS "-Wl,--no-as-needed ${THREADTEST_COMPILE_FLAG}")

显然 gcc 链接器的默认值是--as-needed——链接器选择不链接它认为不需要的库。有趣的是，直接的 g++ 命令行构建正确地决定了需要 libpthread。在 cmake 的情况下，g++ 显然决定不需要 libpthread。您将在上面的make 输出中看到，cmake 将许多带有重复和其他混乱的 g++ 命令行选项组合在一起。我怀疑这可能是根本问题。

不过，这里是 CMakeLists.txt 文件。请注意，至少在我的情况下，根本不需要调用 FIND_PACKAGE(Threads REQUIRED)。

# cmake file for building the ThreadTest executable.  This requires c++11.
CMAKE_MINIMUM_REQUIRED(VERSION 2.8.12)

# !!! Set up the compiler to use, first (i.e. before the PROJECT() call.)
# gcc location.
SET(CROSS_COMPILE_FULL
   "/opt/criticallink/mityomapl138_20151114/sysroots/i686-clsdk-linux/usr/bin/arm-criticallink-linux-gnueabi/arm-criticallink-linux-gnueabi-")
# sysroot location
SET(CROSS_COMPILE_FULL_HOST
   "/opt/criticallink/mityomapl138_20151114/sysroots/arm926ejste-criticallink-linux-gnueabi")
SET(CMAKE_C_COMPILER "${CROSS_COMPILE_FULL}gcc")
SET(CMAKE_CXX_COMPILER "${CROSS_COMPILE_FULL}g++")
SET(CMAKE_FIND_ROOT_PATH "${CROSS_COMPILE_FULL_HOST}")
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

# The project will use the compiler specified above (or the default compiler for Windows.)
PROJECT(CommonSDK)

SET(MY_TEST_HOME "$ENV{TEST_HOME}")
SET(THREADTEST_COMPILE_FLAG "-std=c++11 -pthread")
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${THREADTEST_COMPILE_FLAG}")
SET(CMAKE_EXE_LINKER_FLAGS "-Wl,--no-as-needed ${THREADTEST_COMPILE_FLAG}")

SET(CUR_PROJECT_NAME ThreadTest)
SET(PROJECT_HOME_DIR "${MY_TEST_HOME}/${CUR_PROJECT_NAME}")
SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY "$ENV{TEST_EXEC_HOME}")

FILE(GLOB CUR_PROJECT_FILES "${PROJECT_HOME_DIR}/*.cpp" "${PROJECT_HOME_DIR}/*.h")

ADD_EXECUTABLE(${CUR_PROJECT_NAME} ${CUR_PROJECT_FILES})
TARGET_LINK_LIBRARIES(${CUR_PROJECT_NAME} ${CMAKE_THREAD_LIBS_INIT})

【讨论】：