# - Check if _FILE_OFFSET_BITS macro needed for large files

# CHECK_FILE_OFFSET_BITS ()

#

# The following variables may be set before calling this macro to

# modify the way the check is run:

#

#  CMAKE_REQUIRED_FLAGS = string of compile command line flags

#  CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)

#  CMAKE_REQUIRED_INCLUDES = list of include directories

# Copyright (c) 2009, Michihiro NAKAJIMA

#

# Redistribution and use is allowed according to the terms of the BSD license.

# For details see the accompanying COPYING-CMAKE-SCRIPTS file.

#INCLUDE(CheckCXXSourceCompiles)

GET_FILENAME_COMPONENT(_selfdir_CheckFileOffsetBits

	 "${CMAKE_CURRENT_LIST_FILE}" PATH)

MACRO (CHECK_FILE_OFFSET_BITS)

  IF(NOT DEFINED _FILE_OFFSET_BITS)

    MESSAGE(STATUS "Checking _FILE_OFFSET_BITS for large files")

    TRY_COMPILE(__WITHOUT_FILE_OFFSET_BITS_64

      ${CMAKE_CURRENT_BINARY_DIR}

      ${_selfdir_CheckFileOffsetBits}/CheckFileOffsetBits.c

      COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS})

    IF(NOT __WITHOUT_FILE_OFFSET_BITS_64)

      TRY_COMPILE(__WITH_FILE_OFFSET_BITS_64

        ${CMAKE_CURRENT_BINARY_DIR}

        ${_selfdir_CheckFileOffsetBits}/CheckFileOffsetBits.c

        COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} -D_FILE_OFFSET_BITS=64)

    ENDIF(NOT __WITHOUT_FILE_OFFSET_BITS_64)

    IF(NOT __WITHOUT_FILE_OFFSET_BITS_64 AND __WITH_FILE_OFFSET_BITS_64)

      SET(_FILE_OFFSET_BITS 64 CACHE INTERNAL "_FILE_OFFSET_BITS macro needed for large files")

      MESSAGE(STATUS "Checking _FILE_OFFSET_BITS for large files - needed")

    ELSE(NOT __WITHOUT_FILE_OFFSET_BITS_64 AND __WITH_FILE_OFFSET_BITS_64)

      SET(_FILE_OFFSET_BITS "" CACHE INTERNAL "_FILE_OFFSET_BITS macro needed for large files")

      MESSAGE(STATUS "Checking _FILE_OFFSET_BITS for large files - not needed")

    ENDIF(NOT __WITHOUT_FILE_OFFSET_BITS_64 AND __WITH_FILE_OFFSET_BITS_64)

  ENDIF(NOT DEFINED _FILE_OFFSET_BITS)

ENDMACRO (CHECK_FILE_OFFSET_BITS)