c2eb4b58c0
This describes the module in more details to make upgrading code easier. Additionally, also the CMAKE_HAS_ANSI_STRING_STREAM cache variable is described as it was already briefly documented at the CMakeBackwardCompatibilityCXX module.
71 lines
2.1 KiB
CMake
71 lines
2.1 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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# file LICENSE.rst or https://cmake.org/licensing for details.
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#[=======================================================================[.rst:
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TestForSSTREAM
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--------------
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This module checks whether the C++ standard header ``<sstream>`` exists and
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functions correctly. In early versions of C++ (pre-C++98), this header was not
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formally standardized and may not have been available.
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This module defines the following cache variables:
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``CMAKE_NO_ANSI_STRING_STREAM``
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A cache variable indicating whether the ``<sstream>`` header is available. It
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will be set to value ``0`` if ``<sstream>`` is available (``C++ 98`` and
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newer), and to value ``1`` if ``<sstream>`` is missing (``ANSI C++``).
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``CMAKE_HAS_ANSI_STRING_STREAM``
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A cache variable that is the opposite of ``CMAKE_NO_ANSI_STRING_STREAM``
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(true if ``<sstream>`` is available and false if ``<sstream>`` is missing).
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.. note::
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The ``<sstream>`` header was formally introduced in the ``C++ 98`` standard,
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making this check obsolete for modern compilers.
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Examples
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^^^^^^^^
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Including this module will check for ``<sstream>`` support and define the
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``CMAKE_NO_ANSI_STRING_STREAM`` cache variable:
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.. code-block:: cmake
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include(TestForSSTREAM)
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file(
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CONFIGURE
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OUTPUT config.h
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CONTENT "#cmakedefine CMAKE_NO_ANSI_STRING_STREAM"
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)
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Then it can be used in a C++ program:
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.. code-block:: c++
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#include "config.h"
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#ifndef CMAKE_NO_ANSI_STRING_STREAM
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# include <sstream>
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#endif
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int main() { ... }
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#]=======================================================================]
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if(NOT DEFINED CMAKE_HAS_ANSI_STRING_STREAM)
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message(CHECK_START "Check for sstream")
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try_compile(CMAKE_HAS_ANSI_STRING_STREAM
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SOURCES ${CMAKE_ROOT}/Modules/TestForSSTREAM.cxx
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)
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if (CMAKE_HAS_ANSI_STRING_STREAM)
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message(CHECK_PASS "found")
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set (CMAKE_NO_ANSI_STRING_STREAM 0 CACHE INTERNAL
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"Does the compiler support sstream")
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else ()
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message(CHECK_FAIL "not found")
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set (CMAKE_NO_ANSI_STRING_STREAM 1 CACHE INTERNAL
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"Does the compiler support sstream")
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endif ()
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endif()
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