CMake/Modules/CheckCXXSymbolExists.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
CheckCXXSymbolExists
--------------------

Check if a symbol exists as a function, variable, or macro in C++

.. code-block:: cmake

  CHECK_CXX_SYMBOL_EXISTS(<symbol> <files> <variable>)

Check that the ``<symbol>`` is available after including given header
``<files>`` and store the result in a ``<variable>``.  Specify the list of
files in one argument as a semicolon-separated list.
CHECK_CXX_SYMBOL_EXISTS() can be used to check in C++ files, as
opposed to CHECK_SYMBOL_EXISTS(), which works only for C.

If the header files define the symbol as a macro it is considered
available and assumed to work.  If the header files declare the symbol
as a function or variable then the symbol must also be available for
linking.  If the symbol is a type or enum value it will not be
recognized (consider using CheckTypeSize or CheckCSourceCompiles).

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_LIBRARIES``
   list of libraries to link
``CMAKE_REQUIRED_QUIET``
   execute quietly without messages
#]=======================================================================]

include_guard(GLOBAL)
include(CheckSymbolExists)

macro(CHECK_CXX_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
  __CHECK_SYMBOL_EXISTS_IMPL("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
endmacro()