diff options
| -rw-r--r-- | Modules/CheckTypeSize.cmake | 65 |
1 files changed, 36 insertions, 29 deletions
diff --git a/Modules/CheckTypeSize.cmake b/Modules/CheckTypeSize.cmake index 69f68f9..602170c 100644 --- a/Modules/CheckTypeSize.cmake +++ b/Modules/CheckTypeSize.cmake @@ -7,46 +7,53 @@ CheckTypeSize Check sizeof a type -.. command:: CHECK_TYPE_SIZE +.. command:: check_type_size .. code-block:: cmake - CHECK_TYPE_SIZE(TYPE VARIABLE [BUILTIN_TYPES_ONLY] - [LANGUAGE <language>]) + check_type_size(<type> <variable> [BUILTIN_TYPES_ONLY] + [LANGUAGE <language>]) - Check if the type exists and determine its size. On return, - ``HAVE_${VARIABLE}`` holds the existence of the type, and ``${VARIABLE}`` - holds one of the following: + Check if the type exists and determine its size. Results are reported + in the following variables: - :: + ``HAVE_<variable>`` + Holds a true or false value indicating whether the type exists. - <size> = type has non-zero size <size> - "0" = type has arch-dependent size (see below) - "" = type does not exist + ``<variable>`` + Holds one of the following values: - Both ``HAVE_${VARIABLE}`` and ``${VARIABLE}`` will be created as internal - cache variables. + ``<size>`` + Type has non-zero size ``<size>``. - Furthermore, the variable ``${VARIABLE}_CODE`` holds C preprocessor code - to define the macro ``${VARIABLE}`` to the size of the type, or leave - the macro undefined if the type does not exist. + ``0`` + Type has architecture-dependent size. This may occur when + :variable:`CMAKE_OSX_ARCHITECTURES` has multiple architectures. + In this case ``<variable>_CODE`` contains C preprocessor tests + mapping from each architecture macro to the corresponding type size. + The list of architecture macros is stored in ``<variable>_KEYS``, + and the value for each key is stored in ``<variable>-<key>``. - The variable ``${VARIABLE}`` may be ``0`` when - :variable:`CMAKE_OSX_ARCHITECTURES` has multiple architectures for building - OS X universal binaries. This indicates that the type size varies across - architectures. In this case ``${VARIABLE}_CODE`` contains C preprocessor - tests mapping from each architecture macro to the corresponding type size. - The list of architecture macros is stored in ``${VARIABLE}_KEYS``, and the - value for each key is stored in ``${VARIABLE}-${KEY}``. + "" (empty string) + Type does not exist. - If the ``BUILTIN_TYPES_ONLY`` option is not given, the macro checks for - headers ``<sys/types.h>``, ``<stdint.h>``, and ``<stddef.h>``, and saves - results in ``HAVE_SYS_TYPES_H``, ``HAVE_STDINT_H``, and ``HAVE_STDDEF_H``. - The type size check automatically includes the available headers, thus - supporting checks of types defined in the headers. + ``<variable>_CODE`` + Holds C preprocessor code to define the macro ``<variable>`` to the size + of the type, or to leave the macro undefined if the type does not exist. - If ``LANGUAGE`` is set, the specified compiler will be used to perform the - check. Acceptable values are ``C`` and ``CXX``. + The options are: + + ``BUILTIN_TYPES_ONLY`` + + Support only compiler-builtin types. If *not* given, the macro checks + for headers ``<sys/types.h>``, ``<stdint.h>``, and ``<stddef.h>``, and + saves results in ``HAVE_SYS_TYPES_H``, ``HAVE_STDINT_H``, and + ``HAVE_STDDEF_H``. The type size check automatically includes the + available headers, thus supporting checks of types defined in the headers. + + ``LANGUAGE <language>`` + Use the ``<language>`` compiler to perform the check. + Acceptable values are ``C`` and ``CXX``. Despite the name of the macro you may use it to check the size of more complex expressions, too. To check e.g. for the size of a struct |