CMake/Modules/CMakeDetermineSystem.cmake

# This module is used by the Makefile generator to determin the following variables:
# CMAKE_SYSTEM_NAME - on unix this is uname -s, for windows it is Windows
# CMAKE_SYSTEM_VERSION - on unix this is uname -r, for windows it is empty
# CMAKE_SYSTEM - ${CMAKE_SYSTEM}-${CMAKE_SYSTEM_VERSION}, for windows: ${CMAKE_SYSTEM}
#
#  Expected uname -s output:
#
# AIX                           AIX  
# BSD/OS                        BSD/OS  
# FreeBSD                       FreeBSD  
# HP-UX                         HP-UX  
# IRIX                          IRIX  
# Linux                         Linux  
# NetBSD                        NetBSD  
# OpenBSD                       OpenBSD  
# OFS/1 (Digital Unix)          OSF1  
# SCO OpenServer 5              SCO_SV  
# SCO UnixWare 7                UnixWare  
# SCO UnixWare (pre release 7)  UNIX_SV  
# SCO XENIX                     Xenix  
# Solaris                       SunOS  
# SunOS                         SunOS  
# Tru64                         Tru64  
# Ultrix                        ULTRIX  
# cygwin                        CYGWIN_NT-5.1
# MacOSX                        Darwin


# find out on which system cmake runs
IF(UNIX)
  FIND_PROGRAM(CMAKE_UNAME uname /bin /usr/bin /usr/local/bin )
  IF(CMAKE_UNAME)
    EXEC_PROGRAM(uname ARGS -s OUTPUT_VARIABLE CMAKE_HOST_SYSTEM_NAME)
    EXEC_PROGRAM(uname ARGS -r OUTPUT_VARIABLE CMAKE_HOST_SYSTEM_VERSION)
    IF(CMAKE_HOST_SYSTEM_NAME MATCHES "Linux")
      EXEC_PROGRAM(uname ARGS -m OUTPUT_VARIABLE CMAKE_HOST_SYSTEM_PROCESSOR
        RETURN_VALUE val)
    ELSE(CMAKE_HOST_SYSTEM_NAME MATCHES "Linux")
      EXEC_PROGRAM(uname ARGS -p OUTPUT_VARIABLE CMAKE_HOST_SYSTEM_PROCESSOR
        RETURN_VALUE val)
      IF("${val}" GREATER 0)
        EXEC_PROGRAM(uname ARGS -m OUTPUT_VARIABLE CMAKE_HOST_SYSTEM_PROCESSOR
          RETURN_VALUE val)
      ENDIF("${val}" GREATER 0)
    ENDIF(CMAKE_HOST_SYSTEM_NAME MATCHES "Linux")
    # check the return of the last uname -m or -p 
    IF("${val}" GREATER 0)
        SET(CMAKE_HOST_SYSTEM_PROCESSOR "unknown")
    ENDIF("${val}" GREATER 0)
    SET(CMAKE_UNAME ${CMAKE_UNAME} CACHE INTERNAL "uname command")
    # processor may have double quote in the name, and that needs to be removed
    STRING(REGEX REPLACE "\"" "" CMAKE_HOST_SYSTEM_PROCESSOR "${CMAKE_HOST_SYSTEM_PROCESSOR}")
    STRING(REGEX REPLACE "/" "_" CMAKE_HOST_SYSTEM_PROCESSOR "${CMAKE_HOST_SYSTEM_PROCESSOR}")
  ENDIF(CMAKE_UNAME)
ELSE(UNIX)
  IF(WIN32)
    SET (CMAKE_HOST_SYSTEM_NAME "Windows")
    SET (CMAKE_HOST_SYSTEM_PROCESSOR "$ENV{PROCESSOR_ARCHITECTURE}")
  ENDIF(WIN32)
ENDIF(UNIX)

# if a toolchain file is used, the user wants to cross compile.
# in this case read the toolchain file and keep the CMAKE_HOST_SYSTEM_*
# variables around so they can be used in CMakeLists.txt. 
# In all other cases, the host and target platform are the same.
IF(CMAKE_TOOLCHAIN_FILE)
  # at first try to load it as path relative to the directory from which cmake has been run
  INCLUDE("${CMAKE_BINARY_DIR}/${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
  IF(NOT _INCLUDED_TOOLCHAIN_FILE)
     # if the file isn't found there, check the default locations
     INCLUDE("${CMAKE_TOOLCHAIN_FILE}" OPTIONAL RESULT_VARIABLE _INCLUDED_TOOLCHAIN_FILE)
  ENDIF(NOT _INCLUDED_TOOLCHAIN_FILE)

  IF(_INCLUDED_TOOLCHAIN_FILE)
    SET(CMAKE_TOOLCHAIN_FILE "${_INCLUDED_TOOLCHAIN_FILE}")
  ELSE(_INCLUDED_TOOLCHAIN_FILE)
    MESSAGE(FATAL_ERROR "Could not find toolchain file: ${CMAKE_TOOLCHAIN_FILE}") 
  ENDIF(_INCLUDED_TOOLCHAIN_FILE)
ENDIF(CMAKE_TOOLCHAIN_FILE)


# if CMAKE_SYSTEM_NAME is here already set, either it comes from a toolchain file
# or it was set via -DCMAKE_SYSTEM_NAME=...
# if that's the case, assume we are crosscompiling
IF(CMAKE_SYSTEM_NAME)
  IF(NOT DEFINED CMAKE_CROSSCOMPILING)
    SET(CMAKE_CROSSCOMPILING TRUE)
  ENDIF(NOT DEFINED CMAKE_CROSSCOMPILING)
  SET(PRESET_CMAKE_SYSTEM_NAME TRUE)
ELSE(CMAKE_SYSTEM_NAME)
  SET(CMAKE_SYSTEM_NAME      "${CMAKE_HOST_SYSTEM_NAME}")
  SET(CMAKE_SYSTEM_VERSION   "${CMAKE_HOST_SYSTEM_VERSION}")
  SET(CMAKE_SYSTEM_PROCESSOR "${CMAKE_HOST_SYSTEM_PROCESSOR}")
  SET(CMAKE_CROSSCOMPILING FALSE)
  SET(PRESET_CMAKE_SYSTEM_NAME FALSE)
ENDIF(CMAKE_SYSTEM_NAME)


MACRO(ADJUST_CMAKE_SYSTEM_VARIABLES _PREFIX)
  IF(NOT ${_PREFIX}_NAME)
    SET(${_PREFIX}_NAME "UnknownOS")
  ENDIF(NOT ${_PREFIX}_NAME)

  # fix for BSD/OS , remove the /
  IF(${_PREFIX}_NAME MATCHES BSD.OS)
    SET(${_PREFIX}_NAME BSDOS)
  ENDIF(${_PREFIX}_NAME MATCHES BSD.OS)

  # fix for CYGWIN which has windows version in it 
  IF(${_PREFIX}_NAME MATCHES CYGWIN)
    SET(${_PREFIX}_NAME CYGWIN)
  ENDIF(${_PREFIX}_NAME MATCHES CYGWIN)

  # set CMAKE_SYSTEM to the CMAKE_SYSTEM_NAME
  SET(${_PREFIX}  ${${_PREFIX}_NAME})
  # if there is a CMAKE_SYSTEM_VERSION then add a -${CMAKE_SYSTEM_VERSION}
  IF(${_PREFIX}_VERSION)
    SET(${_PREFIX} ${${_PREFIX}}-${${_PREFIX}_VERSION})
  ENDIF(${_PREFIX}_VERSION)

ENDMACRO(ADJUST_CMAKE_SYSTEM_VARIABLES _PREFIX)

ADJUST_CMAKE_SYSTEM_VARIABLES(CMAKE_SYSTEM)
ADJUST_CMAKE_SYSTEM_VARIABLES(CMAKE_HOST_SYSTEM)

# write entry to the log file
IF(PRESET_CMAKE_SYSTEM_NAME)
  FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 
              "The target system is: ${CMAKE_SYSTEM_NAME} - ${CMAKE_SYSTEM_VERSION} - ${CMAKE_SYSTEM_PROCESSOR}\n")
  FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 
              "The host system is: ${CMAKE_HOST_SYSTEM_NAME} - ${CMAKE_HOST_SYSTEM_VERSION} - ${CMAKE_HOST_SYSTEM_PROCESSOR}\n")
ELSE(PRESET_CMAKE_SYSTEM_NAME)
  FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 
              "The system is: ${CMAKE_SYSTEM_NAME} - ${CMAKE_SYSTEM_VERSION} - ${CMAKE_SYSTEM_PROCESSOR}\n")
ENDIF(PRESET_CMAKE_SYSTEM_NAME)


# if a toolchain file is used use configure_file() to copy it into the 
# build tree, because this way e.g. ${CMAKE_SOURCE_DIR} will be replaced
# with its full path, and so it will also work when used in try_compile()
IF (CMAKE_TOOLCHAIN_FILE)

  SET(_OWN_DIR ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY})
  CONFIGURE_FILE(${CMAKE_TOOLCHAIN_FILE}
               ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeToolchainFile.cmake)

  CONFIGURE_FILE(${CMAKE_ROOT}/Modules/CMakeSystemWithToolchainFile.cmake.in
               ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeSystem.cmake 
               IMMEDIATE @ONLY)
ELSE (CMAKE_TOOLCHAIN_FILE)

  # configure variables set in this file for fast reload, the template file is defined at the top of this file
  CONFIGURE_FILE(${CMAKE_ROOT}/Modules/CMakeSystem.cmake.in
                 ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeSystem.cmake 
                 IMMEDIATE @ONLY)

ENDIF (CMAKE_TOOLCHAIN_FILE)