67 lines
2.0 KiB
CMake
67 lines
2.0 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
|
|
# file LICENSE.rst or https://cmake.org/licensing for details.
|
|
|
|
#[=======================================================================[.rst:
|
|
TestForSTDNamespace
|
|
-------------------
|
|
|
|
This module checks whether the ``CXX`` compiler supports the ``std`` namespace
|
|
for the C++ Standard Library. Early versions of C++ (pre-C++98) did not have a
|
|
requirement for a dedicated namespace of C++ Standard Template Library (STL)
|
|
components (e.g. ``list``, etc.) and other parts of the C++ Standard Library
|
|
(such as I/O streams ``cout``, ``endl``, etc), so they were available globally.
|
|
|
|
This module defines the following cache variable:
|
|
|
|
``CMAKE_NO_STD_NAMESPACE``
|
|
A cache variable containing the result of the check. It will be set to value
|
|
``0`` if the ``std`` namespace is supported (``C++ 98`` and newer), and to
|
|
value ``1`` if not (``ANSI C++``).
|
|
|
|
.. note::
|
|
|
|
The ``std`` namespace got formally introduced in ``C++ 98`` standard, making
|
|
this issue obsolete.
|
|
|
|
Examples
|
|
^^^^^^^^
|
|
|
|
Including this module will check for the ``std`` namespace support and define
|
|
the ``CMAKE_NO_STD_NAMESPACE`` cache variable:
|
|
|
|
.. code-block:: cmake
|
|
|
|
include(TestForSTDNamespace)
|
|
file(
|
|
CONFIGURE
|
|
OUTPUT config.h
|
|
CONTENT "#cmakedefine CMAKE_NO_STD_NAMESPACE"
|
|
)
|
|
|
|
which can be then used in a C++ program to define the missing namespace:
|
|
|
|
.. code-block:: c++
|
|
|
|
#include "config.h"
|
|
|
|
#ifdef CMAKE_NO_STD_NAMESPACE
|
|
# define std
|
|
#endif
|
|
#]=======================================================================]
|
|
|
|
if(NOT DEFINED CMAKE_STD_NAMESPACE)
|
|
message(CHECK_START "Check for STD namespace")
|
|
try_compile(CMAKE_STD_NAMESPACE
|
|
SOURCES ${CMAKE_ROOT}/Modules/TestForSTDNamespace.cxx
|
|
)
|
|
if (CMAKE_STD_NAMESPACE)
|
|
message(CHECK_PASS "found")
|
|
set (CMAKE_NO_STD_NAMESPACE 0 CACHE INTERNAL
|
|
"Does the compiler support std::.")
|
|
else ()
|
|
message(CHECK_FAIL "not found")
|
|
set (CMAKE_NO_STD_NAMESPACE 1 CACHE INTERNAL
|
|
"Does the compiler support std::.")
|
|
endif ()
|
|
endif()
|