sysconf For Node.js

Get configurable system variables.

Requirements and Installation

Linux or macOS, Node.js 24 or later and Rust 1.88 or later are required. Install Rust with rustup and a C compiler for the native linker.

npm install node-sysconf

Installation compiles the native module from source using the included Cargo.lock. There are no prebuilt platform packages. Package managers that block dependency build scripts must allow the node-sysconf install script; for pnpm, approve node-sysconf with pnpm approve-builds and rebuild it with pnpm rebuild node-sysconf. If npm requires script approval, use npm install-scripts approve node-sysconf followed by npm rebuild node-sysconf.

Usage

You can use sysconf function to get the value of system variables.

import { _SC_NPROCESSORS_ONLN, _SC_PAGE_SIZE, sysconf } from "node-sysconf";

console.log(sysconf(_SC_PAGE_SIZE)); // 4096
console.log(sysconf(_SC_NPROCESSORS_ONLN)); // 8

The _SC_* constants from POSIX are exported, along with _SC_PHYS_PAGES, _SC_AVPHYS_PAGES, _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN. Their values depend on the platform.

Return Value

Like the C function, sysconf returns -1 when

• the name is not valid on the current platform,
• the variable has no definite limit, or
• the option is not supported.

A name that is not an integer is treated as an invalid name, so sysconf(1.5) also returns -1.

Some constants are not defined by macOS, such as _SC_AVPHYS_PAGES, _SC_THREAD_ROBUST_PRIO_INHERIT, _SC_THREAD_ROBUST_PRIO_PROTECT and _SC_V7_*. They are still exported on macOS so the same imports work on every platform, but their value is -1 and sysconf always returns -1 for them.

License

MIT