1CMAKE-TOOLCHAINS(7) CMake CMAKE-TOOLCHAINS(7)
2
6 cmake-toolchains - CMake Toolchains Reference
7
9 CMake uses a toolchain of utilities to compile, link libraries and cre‐
10 ate archives, and other tasks to drive the build. The toolchain utili‐
11 ties available are determined by the languages enabled. In normal
12 builds, CMake automatically determines the toolchain for host builds
13 based on system introspection and defaults. In cross-compiling scenar‐
14 ios, a toolchain file may be specified with information about compiler
15 and utility paths.
16
18 Languages are enabled by the project() command. Language-specific
19 built-in variables, such as CMAKE_CXX_COMPILER, CMAKE_CXX_COMPILER_ID
20 etc are set by invoking the project() command. If no project command
21 is in the top-level CMakeLists file, one will be implicitly generated.
22 By default the enabled languages are C and CXX:
23 project(C_Only C)
25 A special value of NONE can also be used with the project() command to
27 enable no languages:
28 project(MyProject NONE)
30 The enable_language() command can be used to enable languages after the
32 project() command:
33 enable_language(CXX)
35 When a language is enabled, CMake finds a compiler for that language,
37 and determines some information, such as the vendor and version of the
38 compiler, the target architecture and bitwidth, the location of corre‐
39 sponding utilities etc.
40 The ENABLED_LANGUAGES global property contains the languages which are
42 currently enabled.
43
45 Several variables relate to the language components of a toolchain
46 which are enabled. CMAKE_<LANG>_COMPILER is the full path to the com‐
47 piler used for <LANG>. CMAKE_<LANG>_COMPILER_ID is the identifier used
48 by CMake for the compiler and CMAKE_<LANG>_COMPILER_VERSION is the ver‐
49 sion of the compiler.
50 The CMAKE_<LANG>_FLAGS variables and the configuration-specific equiva‐
52 lents contain flags that will be added to the compile command when com‐
53 piling a file of a particular language.
54 As the linker is invoked by the compiler driver, CMake needs a way to
56 determine which compiler to use to invoke the linker. This is calcu‐
57 lated by the LANGUAGE of source files in the target, and in the case of
58 static libraries, the language of the dependent libraries. The choice
59 CMake makes may be overridden with the LINKER_LANGUAGE target property.
60
62 CMake provides the try_compile() command and wrapper macros such as
63 CheckCXXSourceCompiles, CheckCXXSymbolExists and CheckIncludeFile to
64 test capability and availability of various toolchain features. These
65 APIs test the toolchain in some way and cache the result so that the
66 test does not have to be performed again the next time CMake runs.
67 Some toolchain features have built-in handling in CMake, and do not
69 require compile-tests. For example, POSITION_INDEPENDENT_CODE allows
70 specifying that a target should be built as position-independent code,
71 if the compiler supports that feature. The <LANG>_VISIBILITY_PRESET and
72 VISIBILITY_INLINES_HIDDEN target properties add flags for hidden visi‐
73 bility, if supported by the compiler.
74
76 If cmake(1) is invoked with the command line parameter
77 -DCMAKE_TOOLCHAIN_FILE=path/to/file, the file will be loaded early to
78 set values for the compilers. The CMAKE_CROSSCOMPILING variable is set
79 to true when CMake is cross-compiling.
80 Cross Compiling for Linux
82 A typical cross-compiling toolchain for Linux has content such as:
83 set(CMAKE_SYSTEM_NAME Linux)
85 set(CMAKE_SYSTEM_PROCESSOR arm)
86 set(CMAKE_SYSROOT /home/devel/rasp-pi-rootfs)
88 set(CMAKE_STAGING_PREFIX /home/devel/stage)
89 set(tools /home/devel/gcc-4.7-linaro-rpi-gnueabihf)
91 set(CMAKE_C_COMPILER ${tools}/bin/arm-linux-gnueabihf-gcc)
92 set(CMAKE_CXX_COMPILER ${tools}/bin/arm-linux-gnueabihf-g++)
93 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
95 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
96 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
97 set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
98 The CMAKE_SYSTEM_NAME is the CMake-identifier of the target platform to
100 build for.
101 The CMAKE_SYSTEM_PROCESSOR is the CMake-identifier of the target archi‐
103 tecture to build for.
104 The CMAKE_SYSROOT is optional, and may be specified if a sysroot is
106 available.
107 The CMAKE_STAGING_PREFIX is also optional. It may be used to specify a
109 path on the host to install to. The CMAKE_INSTALL_PREFIX is always the
110 runtime installation location, even when cross-compiling.
111 The CMAKE_<LANG>_COMPILER variables may be set to full paths, or to
113 names of compilers to search for in standard locations. For
114 toolchains that do not support linking binaries without custom flags or
115 scripts one may set the CMAKE_TRY_COMPILE_TARGET_TYPE variable to
116 STATIC_LIBRARY to tell CMake not to try to link executables during its
117 checks.
118 CMake find_* commands will look in the sysroot, and the
120 CMAKE_FIND_ROOT_PATH entries by default in all cases, as well as look‐
121 ing in the host system root prefix. Although this can be controlled on
122 a case-by-case basis, when cross-compiling, it can be useful to exclude
123 looking in either the host or the target for particular artifacts. Gen‐
124 erally, includes, libraries and packages should be found in the target
125 system prefixes, whereas executables which must be run as part of the
126 build should be found only on the host and not on the target. This is
127 the purpose of the CMAKE_FIND_ROOT_PATH_MODE_* variables.
128 Cross Compiling for the Cray Linux Environment
130 Cross compiling for compute nodes in the Cray Linux Environment can be
131 done without needing a separate toolchain file. Specifying
132 -DCMAKE_SYSTEM_NAME=CrayLinuxEnvironment on the CMake command line will
133 ensure that the appropriate build settings and search paths are config‐
134 ured. The platform will pull its configuration from the current envi‐
135 ronment variables and will configure a project to use the compiler
136 wrappers from the Cray Programming Environment’s PrgEnv-* modules if
137 present and loaded.
138 The default configuration of the Cray Programming Environment is to
140 only support static libraries. This can be overridden and shared
141 libraries enabled by setting the CRAYPE_LINK_TYPE environment variable
142 to dynamic.
143 Running CMake without specifying CMAKE_SYSTEM_NAME will run the config‐
145 ure step in host mode assuming a standard Linux environment. If not
146 overridden, the PrgEnv-* compiler wrappers will end up getting used,
147 which if targeting the either the login node or compute node, is likely
148 not the desired behavior. The exception to this would be if you are
149 building directly on a NID instead of cross-compiling from a login
150 node. If trying to build software for a login node, you will need to
151 either first unload the currently loaded PrgEnv-* module or explicitly
152 tell CMake to use the system compilers in /usr/bin instead of the Cray
153 wrappers. If instead targeting a compute node is desired, just specify
154 the CMAKE_SYSTEM_NAME as mentioned above.
155 Cross Compiling using Clang
157 Some compilers such as Clang are inherently cross compilers. The
158 CMAKE_<LANG>_COMPILER_TARGET can be set to pass a value to those sup‐
159 ported compilers when compiling:
160 set(CMAKE_SYSTEM_NAME Linux)
162 set(CMAKE_SYSTEM_PROCESSOR arm)
163 set(triple arm-linux-gnueabihf)
165 set(CMAKE_C_COMPILER clang)
167 set(CMAKE_C_COMPILER_TARGET ${triple})
168 set(CMAKE_CXX_COMPILER clang++)
169 set(CMAKE_CXX_COMPILER_TARGET ${triple})
170 Similarly, some compilers do not ship their own supplementary utilities
172 such as linkers, but provide a way to specify the location of the
173 external toolchain which will be used by the compiler driver. The
174 CMAKE_<LANG>_COMPILER_EXTERNAL_TOOLCHAIN variable can be set in a
175 toolchain file to pass the path to the compiler driver.
176 Cross Compiling for QNX
178 As the Clang compiler the QNX QCC compile is inherently a cross com‐
179 piler. And the CMAKE_<LANG>_COMPILER_TARGET can be set to pass a value
180 to those supported compilers when compiling:
181 set(CMAKE_SYSTEM_NAME QNX)
183 set(arch gcc_ntoarmv7le)
185 set(CMAKE_C_COMPILER qcc)
187 set(CMAKE_C_COMPILER_TARGET ${arch})
188 set(CMAKE_CXX_COMPILER QCC)
189 set(CMAKE_CXX_COMPILER_TARGET ${arch})
190 Cross Compiling for Windows CE
192 Cross compiling for Windows CE requires the corresponding SDK being
193 installed on your system. These SDKs are usually installed under
194 C:/Program Files (x86)/Windows CE Tools/SDKs.
195 A toolchain file to configure a Visual Studio generator for Windows CE
197 may look like this:
198 set(CMAKE_SYSTEM_NAME WindowsCE)
200 set(CMAKE_SYSTEM_VERSION 8.0)
202 set(CMAKE_SYSTEM_PROCESSOR arm)
203 set(CMAKE_GENERATOR_TOOLSET CE800) # Can be omitted for 8.0
205 set(CMAKE_GENERATOR_PLATFORM SDK_AM335X_SK_WEC2013_V310)
206 The CMAKE_GENERATOR_PLATFORM tells the generator which SDK to use.
208 Further CMAKE_SYSTEM_VERSION tells the generator what version of Win‐
209 dows CE to use. Currently version 8.0 (Windows Embedded Compact 2013)
210 is supported out of the box. Other versions may require one to set
211 CMAKE_GENERATOR_TOOLSET to the correct value.
212 Cross Compiling for Windows 10 Universal Applications
214 A toolchain file to configure a Visual Studio generator for a Windows
215 10 Universal Application may look like this:
216 set(CMAKE_SYSTEM_NAME WindowsStore)
218 set(CMAKE_SYSTEM_VERSION 10.0)
219 A Windows 10 Universal Application targets both Windows Store and Win‐
221 dows Phone. Specify the CMAKE_SYSTEM_VERSION variable to be 10.0 to
222 build with the latest available Windows 10 SDK. Specify a more spe‐
223 cific version (e.g. 10.0.10240.0 for RTM) to build with the correspond‐
224 ing SDK.
225 Cross Compiling for Windows Phone
227 A toolchain file to configure a Visual Studio generator for Windows
228 Phone may look like this:
229 set(CMAKE_SYSTEM_NAME WindowsPhone)
231 set(CMAKE_SYSTEM_VERSION 8.1)
232 Cross Compiling for Windows Store
234 A toolchain file to configure a Visual Studio generator for Windows
235 Store may look like this:
236 set(CMAKE_SYSTEM_NAME WindowsStore)
238 set(CMAKE_SYSTEM_VERSION 8.1)
239 Cross Compiling for Android
241 A toolchain file may configure cross-compiling for Android by setting
242 the CMAKE_SYSTEM_NAME variable to Android. Further configuration is
243 specific to the Android development environment to be used.
244 For Visual Studio Generators, CMake expects NVIDIA Nsight Tegra Visual
246 Studio Edition to be installed. See that section for further configu‐
247 ration details.
248 For Makefile Generators and the Ninja generator, CMake expects one of
250 these environments:
251 · NDK
253 · Standalone Toolchain
255 CMake uses the following steps to select one of the environments:
257 · If the CMAKE_ANDROID_NDK variable is set, the NDK at the specified
259 location will be used.
260 · Else, if the CMAKE_ANDROID_STANDALONE_TOOLCHAIN variable is set, the
262 Standalone Toolchain at the specified location will be used.
263 · Else, if the CMAKE_SYSROOT variable is set to a directory of the form
265 <ndk>/platforms/android-<api>/arch-<arch>, the <ndk> part will be
266 used as the value of CMAKE_ANDROID_NDK and the NDK will be used.
267 · Else, if the CMAKE_SYSROOT variable is set to a directory of the form
269 <standalone-toolchain>/sysroot, the <standalone-toolchain> part will
270 be used as the value of CMAKE_ANDROID_STANDALONE_TOOLCHAIN and the
271 Standalone Toolchain will be used.
272 · Else, if a cmake variable ANDROID_NDK is set it will be used as the
274 value of CMAKE_ANDROID_NDK, and the NDK will be used.
275 · Else, if a cmake variable ANDROID_STANDALONE_TOOLCHAIN is set, it
277 will be used as the value of CMAKE_ANDROID_STANDALONE_TOOLCHAIN, and
278 the Standalone Toolchain will be used.
279 · Else, if an environment variable ANDROID_NDK_ROOT or ANDROID_NDK is
281 set, it will be used as the value of CMAKE_ANDROID_NDK, and the NDK
282 will be used.
283 · Else, if an environment variable ANDROID_STANDALONE_TOOLCHAIN is set
285 then it will be used as the value of CMAKE_ANDROID_STAND‐
286 ALONE_TOOLCHAIN, and the Standalone Toolchain will be used.
287 · Else, an error diagnostic will be issued that neither the NDK or
289 Standalone Toolchain can be found.
290 Cross Compiling for Android with the NDK
292 A toolchain file may configure Makefile Generators or the Ninja genera‐
293 tor to target Android for cross-compiling.
294 Configure use of an Android NDK with the following variables:
296 CMAKE_SYSTEM_NAME
298 Set to Android. Must be specified to enable cross compiling for
299 Android.
300 CMAKE_SYSTEM_VERSION
302 Set to the Android API level. If not specified, the value is
303 determined as follows:
304 · If the CMAKE_ANDROID_API variable is set, its value is used as
306 the API level.
307 · If the CMAKE_SYSROOT variable is set, the API level is
309 detected from the NDK directory structure containing the sys‐
310 root.
311 · Otherwise, the latest API level available in the NDK is used.
313 CMAKE_ANDROID_ARCH_ABI
315 Set to the Android ABI (architecture). If not specified, this
316 variable will default to armeabi. The CMAKE_ANDROID_ARCH vari‐
317 able will be computed from CMAKE_ANDROID_ARCH_ABI automatically.
318 Also see the CMAKE_ANDROID_ARM_MODE and CMAKE_ANDROID_ARM_NEON
319 variables.
320 CMAKE_ANDROID_NDK
322 Set to the absolute path to the Android NDK root directory. A
323 ${CMAKE_ANDROID_NDK}/platforms directory must exist. If not
324 specified, a default for this variable will be chosen as speci‐
325 fied above.
326 CMAKE_ANDROID_NDK_DEPRECATED_HEADERS
328 Set to a true value to use the deprecated per-api-level headers
329 instead of the unified headers. If not specified, the default
330 will be false unless using a NDK that does not provide unified
331 headers.
332 CMAKE_ANDROID_NDK_TOOLCHAIN_VERSION
334 Set to the version of the NDK toolchain to be selected as the
335 compiler. If not specified, the default will be the latest
336 available GCC toolchain.
337 CMAKE_ANDROID_STL_TYPE
339 Set to specify which C++ standard library to use. If not speci‐
340 fied, a default will be selected as described in the variable
341 documentation.
342 The following variables will be computed and provided automatically:
344 CMAKE_<LANG>_ANDROID_TOOLCHAIN_PREFIX
346 The absolute path prefix to the binutils in the NDK toolchain.
347 CMAKE_<LANG>_ANDROID_TOOLCHAIN_SUFFIX
349 The host platform suffix of the binutils in the NDK toolchain.
350 For example, a toolchain file might contain:
352 set(CMAKE_SYSTEM_NAME Android)
354 set(CMAKE_SYSTEM_VERSION 21) # API level
355 set(CMAKE_ANDROID_ARCH_ABI arm64-v8a)
356 set(CMAKE_ANDROID_NDK /path/to/android-ndk)
357 set(CMAKE_ANDROID_STL_TYPE gnustl_static)
358 Alternatively one may specify the values without a toolchain file:
360 $ cmake ../src \
362 -DCMAKE_SYSTEM_NAME=Android \
363 -DCMAKE_SYSTEM_VERSION=21 \
364 -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a \
365 -DCMAKE_ANDROID_NDK=/path/to/android-ndk \
366 -DCMAKE_ANDROID_STL_TYPE=gnustl_static
367 Cross Compiling for Android with a Standalone Toolchain
369 A toolchain file may configure Makefile Generators or the Ninja genera‐
370 tor to target Android for cross-compiling using a standalone toolchain.
371 Configure use of an Android standalone toolchain with the following
373 variables:
374 CMAKE_SYSTEM_NAME
376 Set to Android. Must be specified to enable cross compiling for
377 Android.
378 CMAKE_ANDROID_STANDALONE_TOOLCHAIN
380 Set to the absolute path to the standalone toolchain root direc‐
381 tory. A ${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}/sysroot directory
382 must exist. If not specified, a default for this variable will
383 be chosen as specified above.
384 CMAKE_ANDROID_ARM_MODE
386 When the standalone toolchain targets ARM, optionally set this
387 to ON to target 32-bit ARM instead of 16-bit Thumb. See vari‐
388 able documentation for details.
389 CMAKE_ANDROID_ARM_NEON
391 When the standalone toolchain targets ARM v7, optionally set
392 thisto ON to target ARM NEON devices. See variable documenta‐
393 tion for details.
394 The following variables will be computed and provided automatically:
396 CMAKE_SYSTEM_VERSION
398 The Android API level detected from the standalone toolchain.
399 CMAKE_ANDROID_ARCH_ABI
401 The Android ABI detected from the standalone toolchain.
402 CMAKE_<LANG>_ANDROID_TOOLCHAIN_PREFIX
404 The absolute path prefix to the binutils in the standalone
405 toolchain.
406 CMAKE_<LANG>_ANDROID_TOOLCHAIN_SUFFIX
408 The host platform suffix of the binutils in the standalone
409 toolchain.
410 For example, a toolchain file might contain:
412 set(CMAKE_SYSTEM_NAME Android)
414 set(CMAKE_ANDROID_STANDALONE_TOOLCHAIN /path/to/android-toolchain)
415 Alternatively one may specify the values without a toolchain file:
417 $ cmake ../src \
419 -DCMAKE_SYSTEM_NAME=Android \
420 -DCMAKE_ANDROID_STANDALONE_TOOLCHAIN=/path/to/android-toolchain
421 Cross Compiling for Android with NVIDIA Nsight Tegra Visual Studio Edition
423 A toolchain file to configure one of the Visual Studio Generators to
424 build using NVIDIA Nsight Tegra targeting Android may look like this:
425 set(CMAKE_SYSTEM_NAME Android)
427 The CMAKE_GENERATOR_TOOLSET may be set to select the Nsight Tegra
429 “Toolchain Version” value.
430 See also target properties:
432 · ANDROID_ANT_ADDITIONAL_OPTIONS
434 · ANDROID_API_MIN
436 · ANDROID_API
438 · ANDROID_ARCH
440 · ANDROID_ASSETS_DIRECTORIES
442 · ANDROID_GUI
444 · ANDROID_JAR_DEPENDENCIES
446 · ANDROID_JAR_DIRECTORIES
448 · ANDROID_JAVA_SOURCE_DIR
450 · ANDROID_NATIVE_LIB_DEPENDENCIES
452 · ANDROID_NATIVE_LIB_DIRECTORIES
454 · ANDROID_PROCESS_MAX
456 · ANDROID_PROGUARD_CONFIG_PATH
458 · ANDROID_PROGUARD
460 · ANDROID_SECURE_PROPS_PATH
462 · ANDROID_SKIP_ANT_STEP
464 · ANDROID_STL_TYPE
466
468 2000-2018 Kitware, Inc. and Contributors
4693.11.4 May 13, 2019 CMAKE-TOOLCHAINS(7)