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Help: Add Cross Compiling subsections in cmake-toolchains.7 manual 

Organize the "Cross Compiling" section into subsections by platform.
This will make it easier to add more subsections for more platforms.
This commit is contained in:
Pascal Bach 2014-09-19 12:57:20 +02:00 committed by Brad King
parent 3689c43a8c
commit 0d72451a05
1 changed files with 30 additions and 14 deletions
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44
Help/manual/cmake-toolchains.7.rst
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@ -97,12 +97,20 @@ Cross Compiling
If :manual:`cmake(1)` is invoked with the command line parameter
``-DCMAKE_TOOLCHAIN_FILE=path/to/file``, the file will be loaded early to set
values for the compilers. A typical cross-compiling toolchain has content such
values for the compilers.
The :variable:`CMAKE_CROSSCOMPILING` variable is set to true when CMake is
cross-compiling.
Cross Compiling for Linux
-------------------------
A typical cross-compiling toolchain for Linux has content such
as:
.. code-block:: cmake
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(CMAKE_SYSROOT /home/devel/rasp-pi-rootfs)
set(CMAKE_STAGING_PREFIX /home/devel/stage)
@ -118,6 +126,9 @@ as:
The :variable:`CMAKE_SYSTEM_NAME` is the CMake-identifier of the target platform
to build for.
The :variable:`CMAKE_SYSTEM_PROCESSOR` is the CMake-identifier of the target architecture
to build for.
The :variable:`CMAKE_SYSROOT` is optional, and may be specified if a sysroot
is available.
@ -139,13 +150,17 @@ target system prefixes, whereas executables which must be run as part of the bui
should be found only on the host and not on the target. This is the purpose of
the ``CMAKE_FIND_ROOT_PATH_MODE_*`` variables.
Some compilers are inherently cross compilers, such as Clang and the QNX QCC
compiler. The :variable:`CMAKE_<LANG>_COMPILER_TARGET` can be set to pass a
Cross Compiling using Clang
---------------------------
Some compilers such as Clang are inherently cross compilers.
The :variable:`CMAKE_<LANG>_COMPILER_TARGET` can be set to pass a
value to those supported compilers when compiling:
.. code-block:: cmake
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(triple arm-linux-gnueabihf)
@ -154,7 +169,18 @@ value to those supported compilers when compiling:
set(CMAKE_CXX_COMPILER clang++)
set(CMAKE_CXX_COMPILER_TARGET ${triple})
Or, for QCC:
Similarly, some compilers do not ship their own supplementary utilities
such as linkers, but provide a way to specify the location of the external
toolchain which will be used by the compiler driver. The
:variable:`CMAKE_<LANG>_COMPILER_EXTERNAL_TOOLCHAIN` variable can be set in a
toolchain file to pass the path to the compiler driver.
Cross Compiling for QNX
-----------------------
As the Clang compiler the QNX QCC compile is inherently a cross compiler.
And the :variable:`CMAKE_<LANG>_COMPILER_TARGET` can be set to pass a
value to those supported compilers when compiling:
.. code-block:: cmake
@ -166,13 +192,3 @@ Or, for QCC:
set(CMAKE_C_COMPILER_TARGET ${arch})
set(CMAKE_CXX_COMPILER QCC)
set(CMAKE_CXX_COMPILER_TARGET ${arch})
Similarly, some compilers do not ship their own supplementary utilities
such as linkers, but provide a way to specify the location of the external
toolchain which will be used by the compiler driver. The
:variable:`CMAKE_<LANG>_COMPILER_EXTERNAL_TOOLCHAIN` variable can be set in a
toolchain file to pass the path to the compiler driver.
The :variable:`CMAKE_CROSSCOMPILING` variable is set to true when CMake is
cross-compiling.