diff options
| -rw-r--r-- | configure.ac | 2 | ||||
| -rw-r--r-- | src/libstore/globals.hh | 45 |
2 files changed, 43 insertions, 4 deletions
diff --git a/configure.ac b/configure.ac index 26df39d54..cc7009859 100644 --- a/configure.ac +++ b/configure.ac @@ -11,6 +11,8 @@ AC_PROG_SED # https://git.savannah.gnu.org/cgit/config.git/tree/config.guess # It has the following form, which is not documented anywhere: # <cpu>-<vendor>-<os>[<version>][-<abi>] +# If `./configure` is passed any of the `--host`, `--build`, `--target` options, the value comes from `config.sub` instead: +# https://git.savannah.gnu.org/cgit/config.git/tree/config.sub AC_CANONICAL_HOST AC_MSG_CHECKING([for the canonical Nix system name]) diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh index 76afeb5f5..1fb5927d0 100644 --- a/src/libstore/globals.hh +++ b/src/libstore/globals.hh @@ -193,12 +193,49 @@ public: Setting<std::string> thisSystem{ this, SYSTEM, "system", R"( - This option specifies the canonical Nix system name of the current installation, such as `i686-linux` or `x86_64-darwin`. - Nix can only build derivations whose `system` attribute equals the value specified here. - In general, it never makes sense to modify this value from its default, since you can use it to ‘lie’ about the platform you are building on (e.g., perform a Mac OS build on a Linux machine; the result would obviously be wrong). + The system type of the current Nix installation. + + Nix can only build [derivations](@docroot@/language/derivations.md) whose `system` attribute equals the value specified here. + In general, it never makes sense to modify this value, since you can use it to ‘lie’ about the system you are building on (e.g., perform a macOS build on a Linux machine; the result would obviously be wrong). It only makes sense if the Nix binaries can run on multiple platforms, e.g., ‘universal binaries’ that run on `x86_64-linux` and `i686-linux`. - It defaults to the canonical Nix system name detected by `configure` at build time. + The default value is set when Nix itself is compiled for the system it will run on. + The following system types are widely used, as Nix is actively supported on these platforms: + + - `x86_64-linux` + - `x86_64-darwin` + - `i686-linux` + - `aarch64-linux` + - `aarch64-darwin` + + The concrete value is based on the output of [`config.guess`](https://git.savannah.gnu.org/cgit/config.git/tree/config.guess): + + ``` + <cpu>-<vendor>-<os>[<version>][-<abi>] + ``` + + When Nix is built such that `./configure` is passed any of the `--host`, `--build`, `--target` options, the value is based on the output of [`config.sub`](https://git.savannah.gnu.org/cgit/config.git/tree/config.sub): + + ``` + <cpu>-<vendor>[-<kernel>]-<os> + ``` + + Nix only uses the CPU and OS identifiers: + + ``` + <cpu>-<os>[-<abi>] + ``` + + For historic reasons and backwards-compatibility, some CPU and OS identifiers are transformed as follows: + + | `config.guess` | Nix | + |----------------------------|---------------------| + | `amd64` | `x86_64` | + | `i*86` | `i686` | + | `arm6` | `arm6l` | + | `arm7` | `arm7l` | + | `linux-gnu*` | `linux` | + | `linux-musl*` | `linux` | )"}; Setting<time_t> maxSilentTime{ |