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| -rw-r--r-- | src/doc/reference.md | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/src/doc/reference.md b/src/doc/reference.md index fcf9aefaba8..397abfe563c 100644 --- a/src/doc/reference.md +++ b/src/doc/reference.md @@ -2063,33 +2063,41 @@ arbitrarily complex configurations through nesting. The following configurations must be defined by the implementation: -* `debug_assertions` - Enabled by default when compiling without optimizations. - This can be used to enable extra debugging code in development but not in - production. For example, it controls the behavior of the standard library's - `debug_assert!` macro. -* `target_arch = "..."` - Target CPU architecture, such as `"x86"`, `"x86_64"` - `"mips"`, `"powerpc"`, `"powerpc64"`, `"arm"`, or `"aarch64"`. -* `target_endian = "..."` - Endianness of the target CPU, either `"little"` or - `"big"`. -* `target_env = ".."` - An option provided by the compiler by default - describing the runtime environment of the target platform. Some examples of - this are `musl` for builds targeting the MUSL libc implementation, `msvc` for - Windows builds targeting MSVC, and `gnu` frequently the rest of the time. This - option may also be blank on some platforms. +* `target_arch = "..."` - Target CPU architecture, such as `"x86"`, + `"x86_64"` `"mips"`, `"powerpc"`, `"powerpc64"`, `"arm"`, or + `"aarch64"`. This value is closely related to the first element of + the platform target triple, though it is not identical. +* `target_os = "..."` - Operating system of the target, examples + include `"windows"`, `"macos"`, `"ios"`, `"linux"`, `"android"`, + `"freebsd"`, `"dragonfly"`, `"bitrig"` , `"openbsd"` or + `"netbsd"`. This value is closely related to the second and third + element of the platform target triple, though it is not identical. * `target_family = "..."` - Operating system family of the target, e. g. `"unix"` or `"windows"`. The value of this configuration option is defined as a configuration itself, like `unix` or `windows`. -* `target_os = "..."` - Operating system of the target, examples include - `"windows"`, `"macos"`, `"ios"`, `"linux"`, `"android"`, `"freebsd"`, `"dragonfly"`, - `"bitrig"` , `"openbsd"` or `"netbsd"`. +* `unix` - See `target_family`. +* `windows` - See `target_family`. +* `target_env = ".."` - Further disambiguates the target platform with + information about the ABI/libc. Presently this value is either + `"gnu"`, `"msvc"`, `"musl"`, or the empty string. For historical + reasons this value has only been defined as non-empty when needed + for disambiguation. Thus on many GNU platforms this value will be + empty. This value is closely related to the fourth element of the + platform target triple, though it is not identical. For example, + embedded ABIs such as `gnueabihf` will simply define `target_env` as + `"gnu"`. +* `target_endian = "..."` - Endianness of the target CPU, either `"little"` or + `"big"`. * `target_pointer_width = "..."` - Target pointer width in bits. This is set to `"32"` for targets with 32-bit pointers, and likewise set to `"64"` for 64-bit pointers. * `target_vendor = "..."` - Vendor of the target, for example `apple`, `pc`, or simply `"unknown"`. * `test` - Enabled when compiling the test harness (using the `--test` flag). -* `unix` - See `target_family`. -* `windows` - See `target_family`. +* `debug_assertions` - Enabled by default when compiling without optimizations. + This can be used to enable extra debugging code in development but not in + production. For example, it controls the behavior of the standard library's + `debug_assert!` macro. You can also set another attribute based on a `cfg` variable with `cfg_attr`: |