CMake with iOS Toolchain: Can't Find Threads

Question

I'm trying to use ios-cmake to generate Xcode project targeting iOS. However, it cannot find Threads. Here's a simple CMake script for demonstration:

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)

Running CMake from the terminal:

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

This is the output I got:

-- 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!

I've already triple-checked that pthread.h is located in /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk/usr/include, and besides, it located ZLib and LibXML2 without a problem, so I'm not sure what I'm doing wrong.

> cmake --version
cmake version 2.8.10.2

Answer 1

None of these solutions seem to work. I found the only thing that consistently worked for me was to set the variables that FindThreads.cmake sets. In other words, define the following in your toolchain file:

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)