# - This module determines the thread library of the system.
# The following variables are set
#  CMAKE_THREAD_LIBS_INIT     - the thread library
#  CMAKE_USE_SPROC_INIT       - are we using sproc?
#  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
# For systems with multiple thread libraries, caller can set
#  CMAKE_THREAD_PREFER_PTHREAD

#=============================================================================
# Copyright 2002-2009 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

INCLUDE (CheckIncludeFiles)
INCLUDE (CheckLibraryExists)
SET(Threads_FOUND FALSE)

# Do we have sproc?
IF(CMAKE_SYSTEM MATCHES IRIX AND NOT CMAKE_THREAD_PREFER_PTHREAD)
  CHECK_INCLUDE_FILES("sys/types.h;sys/prctl.h"  CMAKE_HAVE_SPROC_H)
ENDIF()

IF(CMAKE_HAVE_SPROC_H AND NOT CMAKE_THREAD_PREFER_PTHREAD)
  # We have sproc
  SET(CMAKE_USE_SPROC_INIT 1)
ELSE()
  # Do we have pthreads?
  CHECK_INCLUDE_FILES("pthread.h" CMAKE_HAVE_PTHREAD_H)
  IF(CMAKE_HAVE_PTHREAD_H)

    #
    # We have pthread.h
    # Let's check for the library now.
    #
    SET(CMAKE_HAVE_PTHREAD_CREATE 1)
    SET(CMAKE_HAVE_THREADS_LIBRARY 1)
    SET(CMAKE_THREAD_LIBS_INIT "-pthread")
  ENDIF(CMAKE_HAVE_PTHREAD_H)
ENDIF()

IF(CMAKE_THREAD_LIBS_INIT)
  SET(CMAKE_USE_PTHREADS_INIT 1)
  SET(Threads_FOUND TRUE)
ENDIF()

IF(CMAKE_SYSTEM MATCHES "Windows")
  SET(CMAKE_USE_WIN32_THREADS_INIT 1)
  SET(Threads_FOUND TRUE)
ENDIF()

IF(CMAKE_USE_PTHREADS_INIT)
  IF(CMAKE_SYSTEM 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(CMAKE_HAVE_HP_CMA)
    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(CMAKE_USE_PTHREADS_INIT)

INCLUDE(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(Threads DEFAULT_MSG Threads_FOUND)
