Libuv: Process Priorities, Random Bytes, Error Translation, and Metrics

57th chunk of `runtime/doc/luvref.txt`

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 *uv.os_tmpdir()*

                Returns: `string` or `fail`

                WARNING: This function is not thread safe.

uv.os_get_passwd()                                          *uv.os_get_passwd()*

                Returns password file information.

                Returns: `table`
                - `username` : `string`
                - `uid` : `integer`
                - `gid` : `integer`
                - `shell` : `string`
                - `homedir` : `string`

uv.os_getpid()                                                  *uv.os_getpid()*

                Returns the current process ID.

                Returns: `number`

uv.os_getppid()                                                *uv.os_getppid()*

                Returns the parent process ID.

                Returns: `number`

uv.os_getpriority({pid})                                   *uv.os_getpriority()*

                Parameters:
                - `pid`: `integer`

                Returns the scheduling priority of the process specified by
                `pid`.

                Returns: `number` or `fail`

uv.os_setpriority({pid}, {priority})                       *uv.os_setpriority()*

                Parameters:
                - `pid`: `integer`
                - `priority`: `integer`

                Sets the scheduling priority of the process specified by
                `pid`. The `priority` range is between -20 (high priority) and
                19 (low priority).

                Returns: `boolean` or `fail`

uv.random({len}, {flags} [, {callback}])                           *uv.random()*

                Parameters:
                - `len`: `integer`
                - `flags`: `nil` (see below)
                - `callback`: `callable` (async version) or `nil` (sync
                  version)
                  - `err`: `nil` or `string`
                  - `bytes`: `string` or `nil`

                Fills a string of length `len` with cryptographically strong
                random bytes acquired from the system CSPRNG. `flags` is
                reserved for future extension and must currently be `nil` or
                `0` or `{}`.

                Short reads are not possible. When less than `len` random
                bytes are available, a non-zero error value is returned or
                passed to the callback. If the callback is omitted, this
                function is completed synchronously.

                The synchronous version may block indefinitely when not enough
                entropy is available. The asynchronous version may not ever
                finish when the system is low on entropy.

                Returns (sync version): `string` or `fail`

                Returns (async version): `0` or `fail`

uv.translate_sys_error({errcode})                     *uv.translate_sys_error()*

                Parameters:
                - `errcode`: `integer`

                Returns the libuv error message and error name (both in string
                form, see `err` and `name` in |luv-error-handling|) equivalent
                to the given platform dependent error code: POSIX error codes
                on Unix (the ones stored in errno), and Win32 error codes on
                Windows (those returned by GetLastError() or
                WSAGetLastError()).

                Returns: `string, string` or `nil`

==============================================================================
METRICS OPERATIONS                                      *luv-metrics-operations*

uv.metrics_idle_time()                                  *uv.metrics_idle_time()*

                Retrieve the amount of time the event loop has been idle in
                the kernel’s event provider (e.g. `epoll_wait`). The call is
                thread safe.

Title: Libuv: Process Priorities, Random Bytes, Error Translation, and Metrics

Summary

This section covers libuv functions for getting and setting process scheduling priority (`uv.os_getpriority`, `uv.os_setpriority`), generating cryptographically secure random bytes (`uv.random`), translating system error codes (`uv.translate_sys_error`), and retrieving event loop idle time (`uv.metrics_idle_time`). Parameters, return values, and potential failures are documented for each function.