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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
TestForANSIForScope
-------------------
This module checks whether the ``CXX`` compiler restricts the scope of variables
declared in a for-init-statement to the loop body.
Load this module in a CMake project with:
.. code-block:: cmake
include(TestForANSIForScope)
In early C++ (pre-C++98), variables declared in ``for(<init-statement> ...)``
could remain accessible outside the loop after its body (``for() { <body> }``).
This module defines the following cache variable:
``CMAKE_NO_ANSI_FOR_SCOPE``
A cache variable containing the result of the check. It will be set to value
``0`` if the for-init-statement has restricted scope (``C++ 98`` and newer),
and to value ``1`` if not (``ANSI C++``).
.. note::
As of the ``C++ 98`` standard, variables declared in a for-init-statement are
restricted to the loop body, making this behavior obsolete.
Examples
^^^^^^^^
Including this module will check the ``for()`` loop scope behavior and define
the ``CMAKE_NO_ANSI_FOR_SCOPE`` cache variable:
.. code-block:: cmake
:caption: ``CMakeLists.txt``
include(TestForANSIForScope)
file(
CONFIGURE
OUTPUT config.h
CONTENT "#cmakedefine CMAKE_NO_ANSI_FOR_SCOPE"
)
which can be then used in a C++ program:
.. code-block:: c++
:caption: ``example.cxx``
#include "config.h"
#ifdef CMAKE_NO_ANSI_FOR_SCOPE
# define for if(false) {} else for
#endif
See Also
^^^^^^^^
* The :module:`CMakeBackwardCompatibilityCXX` module.
#]=======================================================================]
if(NOT DEFINED CMAKE_ANSI_FOR_SCOPE)
message(CHECK_START "Check for ANSI scope")
try_compile(CMAKE_ANSI_FOR_SCOPE
SOURCES ${CMAKE_ROOT}/Modules/TestForAnsiForScope.cxx
)
if (CMAKE_ANSI_FOR_SCOPE)
message(CHECK_PASS "found")
set (CMAKE_NO_ANSI_FOR_SCOPE 0 CACHE INTERNAL
"Does the compiler support ansi for scope.")
else ()
message(CHECK_FAIL "not found")
set (CMAKE_NO_ANSI_FOR_SCOPE 1 CACHE INTERNAL
"Does the compiler support ansi for scope.")
endif ()
endif()
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