使用iOS工具链进行CMake:找不到线程

Question

我正在尝试使用ios-cmake生成针对iOS的Xcode项目.但是,它找不到Threads.这是一个简单的CMake脚本用于演示:

CMAKE_MINIMUM_REQUIRED (VERSION 2.8)
PROJECT (MyCITest)

SET (CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules")

########################
# EDIT: I've also tried adding the lines below prior to posting this question, 
# but there doesn't seem to be any effect.
# (http://stackoverflow.com/questions/8386897)

SET (CMAKE_REQUIRED_INCLUDES ${CMAKE_IOS_SDK_ROOT}/usr ${CMAKE_IOS_SDK_ROOT}/usr/include)
SET (CMAKE_CXX_FLAGS "--sysroot=${CMAKE_IOS_SDK_ROOT} ${CMAKE_CXX_FLAGS}")
SET (CMAKE_C_FLAGS "--sysroot=${CMAKE_IOS_SDK_ROOT} ${CMAKE_C_FLAGS}")

########################

FIND_PACKAGE (ZLIB REQUIRED)
FIND_PACKAGE (LibXml2 REQUIRED)
FIND_PACKAGE (Threads REQUIRED)

从终端运行CMake:

cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/iOS.cmake -GXcode

这是我得到的输出:

-- Toolchain using default iOS SDK: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk
-- Found ZLIB: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk/usr/lib/libz.dylib (found version "1.2.5") 
-- Found LibXml2: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk/usr/lib/libxml2.dylib (found version "2.7.8") 
-- Looking for include file pthread.h
-- Looking for include file pthread.h - not found
CMake Error at cmake/modules/FindPackageHandleStandardArgs.cmake:97 (MESSAGE):
  Could NOT find Threads (missing: Threads_FOUND)
Call Stack (most recent call first):
  cmake/modules/FindPackageHandleStandardArgs.cmake:288 (_FPHSA_FAILURE_MESSAGE)
  cmake/modules/FindThreads.cmake:166 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:8 (FIND_PACKAGE)


-- Configuring incomplete, errors occurred!

我已经三次检查了pthread.h的位置/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk/usr/include,此外,它找到了ZLib和LibXML2没有问题,所以我不确定我做错了什么.

> cmake --version
cmake version 2.8.10.2

Answer 1

这些解决方案似乎都不起作用.我发现唯一一直对我有用的是设置FindThreads.cmake设置的变量.换句话说,在工具链文件中定义以下内容:

set(CMAKE_THREAD_LIBS_INIT "-lpthread")
set(CMAKE_HAVE_THREADS_LIBRARY 1)
set(CMAKE_USE_WIN32_THREADS_INIT 0)
set(CMAKE_USE_PTHREADS_INIT 1)

Answer 2

事实证明，iOS 工具链目前不支持TRY_COMPILE，它被 所使用CheckIncludeFiles.cmake，而 又被 所使用FindThreads.cmake。TRY_COMPILE当前使用以下命令将工具链设置为跳过：

set (CMAKE_CXX_COMPILER_WORKS TRUE)
set (CMAKE_C_COMPILER_WORKS TRUE)

参考：http://code.google.com/p/ios-cmake/issues/detail? id=1&can=1