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diff --git a/meson/docs/markdown/Builtin-options.md b/meson/docs/markdown/Builtin-options.md new file mode 100644 index 000000000..0536e77bc --- /dev/null +++ b/meson/docs/markdown/Builtin-options.md @@ -0,0 +1,262 @@ +--- +short-description: Built-in options to configure project properties +... + +# Built-in options + +Meson provides two kinds of options: [build options provided by the +build files](Build-options.md) and built-in options that are either +universal options, base options, compiler options. + +## Universal options + +A list of these options can be found by running `meson --help`. All +these can be set by passing `-Doption=value` to `meson` (aka `meson +setup`), or by setting them inside `default_options` of `project()` in +your `meson.build`. Some options can also be set by `--option=value`, +or `--option value`--- a list is shown by running `meson setup +--help`. + +For legacy reasons `--warnlevel` is the cli argument for the +`warning_level` option. + +They can also be edited after setup using `meson configure +-Doption=value`. + +Installation options are all relative to the prefix, except: + +* When the prefix is `/usr`: `sysconfdir` defaults to `/etc`, +* `localstatedir` defaults to `/var`, and `sharedstatedir` defaults to +* `/var/lib` When the prefix is `/usr/local`: `localstatedir` defaults +* to `/var/local`, and `sharedstatedir` defaults to `/var/local/lib` + +### Directories + +| Option | Default value | Description | +| ------ | ------------- | ----------- | +| prefix | see below | Installation prefix | +| bindir | bin | Executable directory | +| datadir | share | Data file directory | +| includedir | include | Header file directory | +| infodir | share/info | Info page directory | +| libdir | see below | Library directory | +| libexecdir | libexec | Library executable directory | +| localedir | share/locale | Locale data directory | +| localstatedir | var | Localstate data directory | +| mandir | share/man | Manual page directory | +| sbindir | sbin | System executable directory | +| sharedstatedir | com | Architecture-independent data directory | +| sysconfdir | etc | Sysconf data directory | + + +`prefix` defaults to `C:/` on Windows, and `/usr/local` otherwise. You +should always override this value. + +`libdir` is automatically detected based on your platform, it should +be correct when doing "native" (build machine == host machine) +compilation. For cross compiles Meson will try to guess the correct +libdir, but it may not be accurate, especially on Linux where +different distributions have different defaults. Using a [cross +file](Cross-compilation.md#defining-the-environment), particularly the +paths section may be necessary. + +### Core options + +Options that are labeled "per machine" in the table are set per +machine. See the [specifying options per +machine](#specifying-options-per-machine) section for details. + +| Option | Default value | Description | Is per machine | Is per subproject | +| ------ | ------------- | ----------- | -------------- | ----------------- | +| auto_features {enabled, disabled, auto} | auto | Override value of all 'auto' features | no | no | +| backend {ninja, vs,<br>vs2010, vs2012, vs2013, vs2015, vs2017, vs2019, xcode} | ninja | Backend to use | no | no | +| buildtype {plain, debug,<br>debugoptimized, release, minsize, custom} | debug | Build type to use | no | no | +| debug | true | Debug | no | no | +| default_library {shared, static, both} | shared | Default library type | no | yes | +| errorlogs | true | Whether to print the logs from failing tests. | no | no | +| install_umask {preserve, 0000-0777} | 022 | Default umask to apply on permissions of installed files | no | no | +| layout {mirror,flat} | mirror | Build directory layout | no | no | +| optimization {0, g, 1, 2, 3, s} | 0 | Optimization level | no | no | +| pkg_config_path {OS separated path} | '' | Additional paths for pkg-config to search before builtin paths | yes | no | +| cmake_prefix_path | [] | Additional prefixes for cmake to search before builtin paths | yes | no | +| stdsplit | true | Split stdout and stderr in test logs | no | no | +| strip | false | Strip targets on install | no | no | +| unity {on, off, subprojects} | off | Unity build | no | no | +| unity_size {>=2} | 4 | Unity file block size | no | no | +| warning_level {0, 1, 2, 3} | 1 | Set the warning level. From 0 = none to 3 = highest | no | yes | +| werror | false | Treat warnings as errors | no | yes | +| wrap_mode {default, nofallback,<br>nodownload, forcefallback, nopromote} | default | Wrap mode to use | no | no | +| force_fallback_for | [] | Force fallback for those dependencies | no | no | + +<a name="build-type-options"></a> For setting optimization levels and +toggling debug, you can either set the `buildtype` option, or you can +set the `optimization` and `debug` options which give finer control +over the same. Whichever you decide to use, the other will be deduced +from it. For example, `-Dbuildtype=debugoptimized` is the same as +`-Ddebug=true -Doptimization=2` and vice-versa. This table documents +the two-way mapping: + +| buildtype | debug | optimization | +| --------- | ----- | ------------ | +| plain | false | 0 | +| debug | true | 0 | +| debugoptimized | true | 2 | +| release | false | 3 | +| minsize | true | s | + +All other combinations of `debug` and `optimization` set `buildtype` to `'custom'`. + +## Base options + +These are set in the same way as universal options, either by +`-Doption=value`, or by setting them inside `default_options` of +`project()` in your `meson.build`. However, they cannot be shown in +the output of `meson --help` because they depend on both the current +platform and the compiler that will be selected. The only way to see +them is to setup a builddir and then run `meson configure` on it with +no options. + +The following options are available. Note that they may not be +available on all platforms or with all compilers: + +| Option | Default value | Possible values | Description | +|---------------|----------------|------------------------------------------------------------------|-------------------------------------------------------------------------------| +| b_asneeded | true | true, false | Use -Wl,--as-needed when linking | +| b_bitcode | false | true, false | Embed Apple bitcode, see below | +| b_colorout | always | auto, always, never | Use colored output | +| b_coverage | false | true, false | Enable coverage tracking | +| b_lundef | true | true, false | Don't allow undefined symbols when linking | +| b_lto | false | true, false | Use link time optimization | +| b_lto_threads | 0 | Any integer* | Use multiple threads for lto. *(Added in 0.57.0)* | +| b_lto_mode | default | default, thin | Select between lto modes, thin and default. *(Added in 0.57.0)* | +| b_ndebug | false | true, false, if-release | Disable asserts | +| b_pch | true | true, false | Use precompiled headers | +| b_pgo | off | off, generate, use | Use profile guided optimization | +| b_sanitize | none | see below | Code sanitizer to use | +| b_staticpic | true | true, false | Build static libraries as position independent | +| b_pie | false | true, false | Build position-independent executables (since 0.49.0) | +| b_vscrt | from_buildtype | none, md, mdd, mt, mtd, from_buildtype, static_from_buildtype | VS runtime library to use (since 0.48.0) (static_from_buildtype since 0.56.0) | + +The value of `b_sanitize` can be one of: `none`, `address`, `thread`, +`undefined`, `memory`, `address,undefined`, but note that some +compilers might not support all of them. For example Visual Studio +only supports the address sanitizer. + +* < 0 means disable, == 0 means automatic selection, > 0 sets a specific number to use + +LLVM supports `thin` lto, for more discussion see [LLVM's documentation](https://clang.llvm.org/docs/ThinLTO.html) + +<a name="b_vscrt-from_buildtype"></a> +The default value of `b_vscrt` is `from_buildtype`. The following table is +used internally to pick the CRT compiler arguments for `from_buildtype` or +`static_from_buildtype` *(since 0.56)* based on the value of the `buildtype` +option: + +| buildtype | from_buildtype | static_from_buildtype | +| -------- | -------------- | --------------------- | +| debug | `/MDd` | `/MTd` | +| debugoptimized | `/MD` | `/MT` | +| release | `/MD` | `/MT` | +| minsize | `/MD` | `/MT` | +| custom | error! | error! | + +### Notes about Apple Bitcode support + +`b_bitcode` will pass `-fembed-bitcode` while compiling and will pass +`-Wl,-bitcode_bundle` while linking. These options are incompatible +with `b_asneeded`, so that option will be silently disabled. + +[Shared modules](Reference-manual.md#shared_module) will not have +bitcode embedded because `-Wl,-bitcode_bundle` is incompatible with +both `-bundle` and `-Wl,-undefined,dynamic_lookup` which are necessary +for shared modules to work. + +## Compiler options + +Same caveats as base options above. + +The following options are available. They can be set by passing +`-Doption=value` to `meson`. Note that both the options themselves and +the possible values they can take will depend on the target platform +or compiler being used: + +| Option | Default value | Possible values | Description | +| ------ | ------------- | --------------- | ----------- | +| c_args | | free-form comma-separated list | C compile arguments to use | +| c_link_args | | free-form comma-separated list | C link arguments to use | +| c_std | none | none, c89, c99, c11, c17, c18, c2x, gnu89, gnu99, gnu11, gnu17, gnu18, gnu2x | C language standard to use | +| c_winlibs | see below | free-form comma-separated list | Standard Windows libs to link against | +| c_thread_count | 4 | integer value ≥ 0 | Number of threads to use with emcc when using threads | +| cpp_args | | free-form comma-separated list | C++ compile arguments to use | +| cpp_link_args | | free-form comma-separated list | C++ link arguments to use | +| cpp_std | none | none, c++98, c++03, c++11, c++14, c++17, c++20 <br/>c++2a, c++1z, gnu++03, gnu++11, gnu++14, gnu++17, gnu++1z, <br/> gnu++2a, gnu++20, vc++14, vc++17, vc++latest | C++ language standard to use | +| cpp_debugstl | false | true, false | C++ STL debug mode | +| cpp_eh | default | none, default, a, s, sc | C++ exception handling type | +| cpp_rtti | true | true, false | Whether to enable RTTI (runtime type identification) | +| cpp_thread_count | 4 | integer value ≥ 0 | Number of threads to use with emcc when using threads | +| cpp_winlibs | see below | free-form comma-separated list | Standard Windows libs to link against | +| fortran_std | none | [none, legacy, f95, f2003, f2008, f2018] | Fortran language standard to use | +| cuda_ccbindir | | filesystem path | CUDA non-default toolchain directory to use (-ccbin) *(Added in 0.57.1)* | + +The default values of `c_winlibs` and `cpp_winlibs` are in +compiler-specific argument forms, but the libraries are: kernel32, +user32, gdi32, winspool, shell32, ole32, oleaut32, uuid, comdlg32, +advapi32. + +All these `<lang>_*` options are specified per machine. See below in +the [specifying options per machine](#specifying-options-per-machine) +section on how to do this in cross builds. + +When using MSVC, `cpp_eh=none` will result in no exception flags being +passed, while the `cpp_eh=[value]` will result in `/EH[value]`. Since +*0.51.0* `cpp_eh=default` will result in `/EHsc` on MSVC. When using +gcc-style compilers, nothing is passed (allowing exceptions to work), +while `cpp_eh=none` passes `-fno-exceptions`. + +Since *0.54.0* The `<lang>_thread_count` option can be used to control +the value passed to `-s PTHREAD_POOL_SIZE` when using emcc. No other +c/c++ compiler supports this option. + +## Specifying options per machine + +Since *0.51.0*, some options are specified per machine rather than +globally for all machine configurations. Prefixing the option with +`build.` just affects the build machine configuration, while +unprefixed just affects the host machine configuration, respectively. +For example: + + - `build.pkg_config_path` controls the paths pkg-config will search + for just `native: true` dependencies (build machine). + + - `pkg_config_path` controls the paths pkg-config will search for + just `native: false` dependencies (host machine). + +This is useful for cross builds. In the native builds, build = host, +and the unprefixed option alone will suffice. + +Prior to *0.51.0*, these options just effected native builds when +specified on the command line, as there was no `build.` prefix. +Similarly named fields in the `[properties]` section of the cross file +would effect cross compilers, but the code paths were fairly different +allowing differences in behavior to crop out. + +## Specifying options per subproject + +Since *0.54.0* `default_library` and `werror` built-in options can be +defined per subproject. This is useful for example when building +shared libraries in the main project, but static link a subproject, or +when the main project must build with no warnings but some subprojects +cannot. + +Most of the time this would be used either by the parent project by +setting subproject's default_options (e.g. `subproject('foo', +default_options: 'default_library=static')`), or by the user using the +command line `-Dfoo:default_library=static`. + +The value is overridden in this order: +- Value from parent project +- Value from subproject's default_options if set +- Value from subproject() default_options if set +- Value from command line if set + +Since 0.56.0 `warning_level` can also be defined per subproject. |