# Distributed under the OSI-approved BSD 3-Clause License. See accompanying # file Copyright.txt or https://cmake.org/licensing for details. #[=======================================================================[.rst: FindThreads ----------- This module determines the thread library of the system. The following variables are set :: CMAKE_THREAD_LIBS_INIT - the thread library CMAKE_USE_WIN32_THREADS_INIT - using WIN32 threads? CMAKE_USE_PTHREADS_INIT - are we using pthreads CMAKE_HP_PTHREADS_INIT - are we using hp pthreads The following import target is created :: Threads::Threads If the use of the -pthread compiler and linker flag is preferred then the caller can set :: THREADS_PREFER_PTHREAD_FLAG The compiler flag can only be used with the imported target. Use of both the imported target as well as this switch is highly recommended for new code. #]=======================================================================] include (CheckLibraryExists) include (CheckSymbolExists) set(Threads_FOUND FALSE) set(CMAKE_REQUIRED_QUIET_SAVE ${CMAKE_REQUIRED_QUIET}) set(CMAKE_REQUIRED_QUIET ${Threads_FIND_QUIETLY}) if(CMAKE_C_COMPILER_LOADED) include (CheckIncludeFile) elseif(CMAKE_CXX_COMPILER_LOADED) include (CheckIncludeFileCXX) else() message(FATAL_ERROR "FindThreads only works if either C or CXX language is enabled") endif() # Internal helper macro. # Do NOT even think about using it outside of this file! macro(_check_threads_lib LIBNAME FUNCNAME VARNAME) if(NOT Threads_FOUND) CHECK_LIBRARY_EXISTS(${LIBNAME} ${FUNCNAME} "" ${VARNAME}) if(${VARNAME}) set(CMAKE_THREAD_LIBS_INIT "-l${LIBNAME}") set(CMAKE_HAVE_THREADS_LIBRARY 1) set(Threads_FOUND TRUE) endif() endif () endmacro() # Internal helper macro. # Do NOT even think about using it outside of this file! macro(_check_pthreads_flag) if(NOT Threads_FOUND) # If we did not found -lpthread, -lpthread, or -lthread, look for -pthread if(NOT DEFINED THREADS_HAVE_PTHREAD_ARG) message(STATUS "Check if compiler accepts -pthread") if(CMAKE_C_COMPILER_LOADED) set(_threads_src ${CMAKE_CURRENT_LIST_DIR}/CheckForPthreads.c) elseif(CMAKE_CXX_COMPILER_LOADED) set(_threads_src ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/FindThreads/CheckForPthreads.cxx) configure_file(${CMAKE_CURRENT_LIST_DIR}/CheckForPthreads.c "${_threads_src}" COPYONLY) endif() try_compile(THREADS_HAVE_PTHREAD_ARG ${CMAKE_BINARY_DIR} ${_threads_src} CMAKE_FLAGS -DLINK_LIBRARIES:STRING=-pthread OUTPUT_VARIABLE OUTPUT) unset(_threads_src) if(THREADS_HAVE_PTHREAD_ARG) set(Threads_FOUND TRUE) message(STATUS "Check if compiler accepts -pthread - yes") else() message(STATUS "Check if compiler accepts -pthread - no") file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log "Determining if compiler accepts -pthread failed with the following output:\n${OUTPUT}\n\n") endif() endif() if(THREADS_HAVE_PTHREAD_ARG) set(Threads_FOUND TRUE) set(CMAKE_THREAD_LIBS_INIT "-pthread") endif() endif() endmacro() # Do we have pthreads? if(CMAKE_C_COMPILER_LOADED) CHECK_INCLUDE_FILE("pthread.h" CMAKE_HAVE_PTHREAD_H) else() CHECK_INCLUDE_FILE_CXX("pthread.h" CMAKE_HAVE_PTHREAD_H) endif() if(CMAKE_HAVE_PTHREAD_H) # # We have pthread.h # Let's check for the library now. # set(CMAKE_HAVE_THREADS_LIBRARY) if(NOT THREADS_HAVE_PTHREAD_ARG) # Check if pthread functions are in normal C library. CHECK_SYMBOL_EXISTS(pthread_create pthread.h CMAKE_HAVE_LIBC_CREATE) if(CMAKE_HAVE_LIBC_CREATE) set(CMAKE_THREAD_LIBS_INIT "") set(CMAKE_HAVE_THREADS_LIBRARY 1) set(Threads_FOUND TRUE) else() # Check for -pthread first if enabled. This is the recommended # way, but not backwards compatible as one must also pass -pthread # as compiler flag then. if (THREADS_PREFER_PTHREAD_FLAG) _check_pthreads_flag() endif () _check_threads_lib(pthreads pthread_create CMAKE_HAVE_PTHREADS_CREATE) _check_threads_lib(pthread pthread_create CMAKE_HAVE_PTHREAD_CREATE) if(CMAKE_SYSTEM_NAME MATCHES "SunOS") # On sun also check for -lthread _check_threads_lib(thread thr_create CMAKE_HAVE_THR_CREATE) endif() endif() endif() _check_pthreads_flag() endif() if(CMAKE_THREAD_LIBS_INIT OR CMAKE_HAVE_LIBC_CREATE) set(CMAKE_USE_PTHREADS_INIT 1) set(Threads_FOUND TRUE) endif() if(CMAKE_SYSTEM_NAME MATCHES "Windows") set(CMAKE_USE_WIN32_THREADS_INIT 1) set(Threads_FOUND TRUE) endif() if(CMAKE_USE_PTHREADS_INIT) if(CMAKE_SYSTEM_NAME MATCHES "HP-UX") # Use libcma if it exists and can be used. It provides more # symbols than the plain pthread library. CMA threads # have actually been deprecated: # http://docs.hp.com/en/B3920-90091/ch12s03.html#d0e11395 # http://docs.hp.com/en/947/d8.html # but we need to maintain compatibility here. # The CMAKE_HP_PTHREADS setting actually indicates whether CMA threads # are available. CHECK_LIBRARY_EXISTS(cma pthread_attr_create "" CMAKE_HAVE_HP_CMA) if(CMAKE_HAVE_HP_CMA) set(CMAKE_THREAD_LIBS_INIT "-lcma") set(CMAKE_HP_PTHREADS_INIT 1) set(Threads_FOUND TRUE) endif() set(CMAKE_USE_PTHREADS_INIT 1) endif() if(CMAKE_SYSTEM MATCHES "OSF1-V") set(CMAKE_USE_PTHREADS_INIT 0) set(CMAKE_THREAD_LIBS_INIT ) endif() if(CMAKE_SYSTEM MATCHES "CYGWIN_NT") set(CMAKE_USE_PTHREADS_INIT 1) set(Threads_FOUND TRUE) set(CMAKE_THREAD_LIBS_INIT ) set(CMAKE_USE_WIN32_THREADS_INIT 0) endif() endif() set(CMAKE_REQUIRED_QUIET ${CMAKE_REQUIRED_QUIET_SAVE}) include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake) FIND_PACKAGE_HANDLE_STANDARD_ARGS(Threads DEFAULT_MSG Threads_FOUND) if(THREADS_FOUND AND NOT TARGET Threads::Threads) add_library(Threads::Threads INTERFACE IMPORTED) if(THREADS_HAVE_PTHREAD_ARG) set_property(TARGET Threads::Threads PROPERTY INTERFACE_COMPILE_OPTIONS "$<$:SHELL:-Xcompiler -pthread>" "$<$>:-pthread>") endif() if(CMAKE_THREAD_LIBS_INIT) set_property(TARGET Threads::Threads PROPERTY INTERFACE_LINK_LIBRARIES "${CMAKE_THREAD_LIBS_INIT}") endif() endif()