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# Ceres Solver - A fast non-linear least squares minimizer
# Copyright 2017 Google Inc. All rights reserved.
# http://ceres-solver.org/
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * Neither the name of Google Inc. nor the names of its contributors may be
# used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
#
# Author: alexs.mac@gmail.com (Alex Stewart)
# Adds Ceres' C++11 requirements to a target such that they are exported when
# the target is exported (if the version of CMake supports it).
#
# add_ceres_cxx11_requirements_to_target( [target1 [target2 [...]]] )
function(add_ceres_cxx11_requirements_to_target)
include(CheckCXXCompilerFlag)
check_cxx_compiler_flag("-std=c++11" COMPILER_HAS_CXX11_FLAG)
foreach(TARGET ${ARGN})
if (NOT TARGET ${TARGET})
message(FATAL_ERROR "Specified target to append Ceres C++11 requirements "
"to: ${TARGET} is not a declared CMake target.")
endif()
if (COMPILER_HAS_CXX11_FLAG)
# IMPORTANT: It is not sufficient to specify the
# CXX_STANDARD/CXX_STANDARD_REQUIRED target properties
# as these target properties are NOT exported.
if (CMAKE_VERSION VERSION_LESS "2.8.12")
# CMake version < 2.8.12 does not support target_compile_options(), warn
# user that they will have to add compile flags to their own projects
# manually.
message(WARNING "-- Warning: Detected CMake version: ${CMAKE_VERSION} "
"< 2.8.12, which is the minimum required for compile options to be "
"included in an exported CMake target and the detected. compiler "
"requires -std=c++11. The client is responsible for adding "
"-std=c++11 when linking against: ${TARGET}.")
elseif (COMMAND target_compile_features)
# CMake >= 3.1, use new target_compile_features() to specify Ceres'
# C++11 requirements as used in the public API. This assumes that
# C++11 STL features are available if the specified features are
# available. We do not use the cxx_std_11 feature to specify this as
# this did not come in until CMake 3.8.
#
# The reason to prefer using target_compile_features() if it exists is
# that this handles 'upgrading' of the C++ standard required more
# gracefully, e.g. if a client of Ceres requires C++14, but Ceres was
# compiled against C++11 then target_compile_options() may not work as
# expected.
target_compile_features(
${TARGET} PUBLIC cxx_alignas cxx_alignof cxx_constexpr)
else()
# CMake version >= 2.8.12 && < 3.1 supports target_compile_options()
# but not target_compile_features(). For these intermediary versions,
# we use target_compile_options() to manually specify the C++11 flag and
# export it for client targets that depend on the target iff they are
# NOT compiling for C. We check for not C, rather than C++ as
# LINKER_LANGUAGE is often NOTFOUND and then uses the default (C++).
target_compile_options(${TARGET} PUBLIC
$<$<NOT:$<STREQUAL:$<TARGET_PROPERTY:LINKER_LANGUAGE>,C>>:-std=c++11>)
endif()
endif()
endforeach()
endfunction()