CMake/Modules/CheckIncludeFileCXX.cmake
Brad King 86578eccf2 Simplify CMake per-source license notices
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool.  Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience.  Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.

Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices.  It also references version control
history for more precise information.  Therefore we no longer need to spell
out the list of Contributors in each source file notice.

Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing".  The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.

Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically.  Manually fix up shebang lines and trailing
newlines in a few files.  Manually update the notices in a few files that the
script does not handle.
2016-09-27 15:14:44 -04:00

89 lines
3.2 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#.rst:
# CheckIncludeFileCXX
# -------------------
#
# Provides a macro to check if a header file can be included in ``CXX``.
#
# .. command:: CHECK_INCLUDE_FILE_CXX
#
# ::
#
# CHECK_INCLUDE_FILE_CXX(<include> <variable> [<flags>])
#
# Check if the given ``<include>`` file may be included in a ``CXX``
# source file and store the result in an internal cache entry named
# ``<variable>``. The optional third argument may be used to add
# compilation flags to the check (or use ``CMAKE_REQUIRED_FLAGS`` below).
#
# 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
# ``CMAKE_REQUIRED_QUIET``
# execute quietly without messages
#
# See modules :module:`CheckIncludeFile` and :module:`CheckIncludeFiles`
# to check for one or more ``C`` headers.
macro(CHECK_INCLUDE_FILE_CXX INCLUDE VARIABLE)
if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}")
if(CMAKE_REQUIRED_INCLUDES)
set(CHECK_INCLUDE_FILE_CXX_INCLUDE_DIRS "-DINCLUDE_DIRECTORIES=${CMAKE_REQUIRED_INCLUDES}")
else()
set(CHECK_INCLUDE_FILE_CXX_INCLUDE_DIRS)
endif()
set(MACRO_CHECK_INCLUDE_FILE_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(CHECK_INCLUDE_FILE_VAR ${INCLUDE})
configure_file(${CMAKE_ROOT}/Modules/CheckIncludeFile.cxx.in
${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckIncludeFile.cxx)
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Looking for C++ include ${INCLUDE}")
endif()
if(${ARGC} EQUAL 3)
set(CMAKE_CXX_FLAGS_SAVE ${CMAKE_CXX_FLAGS})
string(APPEND CMAKE_CXX_FLAGS " ${ARGV2}")
endif()
try_compile(${VARIABLE}
${CMAKE_BINARY_DIR}
${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckIncludeFile.cxx
COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
CMAKE_FLAGS
-DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_INCLUDE_FILE_FLAGS}
"${CHECK_INCLUDE_FILE_CXX_INCLUDE_DIRS}"
OUTPUT_VARIABLE OUTPUT)
if(${ARGC} EQUAL 3)
set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS_SAVE})
endif()
if(${VARIABLE})
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Looking for C++ include ${INCLUDE} - found")
endif()
set(${VARIABLE} 1 CACHE INTERNAL "Have include ${INCLUDE}")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"Determining if the include file ${INCLUDE} "
"exists passed with the following output:\n"
"${OUTPUT}\n\n")
else()
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Looking for C++ include ${INCLUDE} - not found")
endif()
set(${VARIABLE} "" CACHE INTERNAL "Have include ${INCLUDE}")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"Determining if the include file ${INCLUDE} "
"exists failed with the following output:\n"
"${OUTPUT}\n\n")
endif()
endif()
endmacro()