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| author | Craig Scott <craig.scott@crascit.com> | 2022-01-15 20:45:01 (GMT) |
|---|---|---|
| committer | Kitware Robot <kwrobot@kitware.com> | 2022-01-15 20:45:08 (GMT) |
| commit | b74887888039ee7be3c7c1d1b2b92b1368be682e (patch) | |
| tree | 721d91aecb8b1d78134a99fb16d851530cd708e2 /Help | |
| parent | d9a8744c50a180a1d8578baaeccf4e5f5f1986b4 (diff) | |
| parent | acd65d78c462b3525e6bc6276cbf4d907804c399 (diff) | |
| download | CMake-b74887888039ee7be3c7c1d1b2b92b1368be682e.zip CMake-b74887888039ee7be3c7c1d1b2b92b1368be682e.tar.gz CMake-b74887888039ee7be3c7c1d1b2b92b1368be682e.tar.bz2 | |
Merge topic 'doc-LANG_STANDARD_REQUIRED'
acd65d78c4 Help: Actual language standard can be higher than <LANG>_STANDARD
Acked-by: Kitware Robot <kwrobot@kitware.com>
Reviewed-by: Raul Tambre <raul@tambre.ee>
Merge-request: !6870
Diffstat (limited to 'Help')
| -rw-r--r-- | Help/prop_tgt/LANG_STANDARD.rst | 7 | ||||
| -rw-r--r-- | Help/prop_tgt/LANG_STANDARD_REQUIRED.rst | 16 |
2 files changed, 18 insertions, 5 deletions
diff --git a/Help/prop_tgt/LANG_STANDARD.rst b/Help/prop_tgt/LANG_STANDARD.rst index bd377ec..c83da01 100644 --- a/Help/prop_tgt/LANG_STANDARD.rst +++ b/Help/prop_tgt/LANG_STANDARD.rst @@ -15,6 +15,13 @@ newer standard is specified than is supported by the compiler, then it will fallback to the latest supported standard. This "decay" behavior may be controlled with the :prop_tgt:`<LANG>_STANDARD_REQUIRED` target property. +Note that the actual language standard used may be higher than that specified +by ``<LANG>_STANDARD``, regardless of the value of +:prop_tgt:`<LANG>_STANDARD_REQUIRED`. In particular, +:ref:`transitive usage requirements <Target Usage Requirements>` or the use of +:manual:`compile features <cmake-compile-features(7)>` can raise the required +language standard above what ``<LANG>_STANDARD`` specifies. + These properties are initialized by the value of the :variable:`CMAKE_<LANG>_STANDARD` variable if it is set when a target is created. diff --git a/Help/prop_tgt/LANG_STANDARD_REQUIRED.rst b/Help/prop_tgt/LANG_STANDARD_REQUIRED.rst index 56ecef8..e61125b 100644 --- a/Help/prop_tgt/LANG_STANDARD_REQUIRED.rst +++ b/Help/prop_tgt/LANG_STANDARD_REQUIRED.rst @@ -11,16 +11,22 @@ The variations are: * :prop_tgt:`OBJCXX_STANDARD_REQUIRED` These properties specify whether the value of :prop_tgt:`<LANG>_STANDARD` is a -requirement. When ``OFF`` or unset, the :prop_tgt:`<LANG>_STANDARD` target +requirement. When false or unset, the :prop_tgt:`<LANG>_STANDARD` target property is treated as optional and may "decay" to a previous standard if the -requested is not available. +requested standard is not available. When ``<LANG>_STANDARD_REQUIRED`` is set +to true, :prop_tgt:`<LANG>_STANDARD` becomes a hard requirement and a fatal +error will be issued if that requirement cannot be met. + +Note that the actual language standard used may be higher than that specified +by :prop_tgt:`<LANG>_STANDARD`, regardless of the value of +``<LANG>_STANDARD_REQUIRED``. In particular, +:ref:`transitive usage requirements <Target Usage Requirements>` or the use of +:manual:`compile features <cmake-compile-features(7)>` can raise the required +language standard above what :prop_tgt:`<LANG>_STANDARD` specifies. These properties are initialized by the value of the :variable:`CMAKE_<LANG>_STANDARD_REQUIRED` variable if it is set when a target is created. -For supported CMake versions see the respective pages. -To control language standard versions see :prop_tgt:`<LANG>_STANDARD`. - See the :manual:`cmake-compile-features(7)` manual for information on compile features and a list of supported compilers. |