# - MACRO_ENSURE_OUT_OF_SOURCE_BUILD(<errorMessage>)
# MACRO_ENSURE_OUT_OF_SOURCE_BUILD(<errorMessage>)

# Copyright (c) 2006, Alexander Neundorf, <neundorf@kde.org>
#
# Redistribution and use is allowed according to the terms of the BSD license:
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# 1. Redistributions of source code must retain the copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products 
#    derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

macro (MACRO_ENSURE_OUT_OF_SOURCE_BUILD _errorMessage)

   string(COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${CMAKE_BINARY_DIR}" _insource)
   if (_insource)
     message(SEND_ERROR "${_errorMessage}")
     message(FATAL_ERROR "Remove the file CMakeCache.txt in ${CMAKE_SOURCE_DIR} first.")
   endif (_insource)

endmacro (MACRO_ENSURE_OUT_OF_SOURCE_BUILD)