mirror of
https://github.com/Kitware/CMake.git
synced 2025-10-14 02:08:27 +08:00
26dd965037
This is mainly a sync with other CMake modules for consistency: - Added intro code blocks showing how to include the modules. - Adjusted examples sections. - Added "See Also" sections.
80 lines
2.2 KiB
CMake
80 lines
2.2 KiB
CMake
# 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()
|