Linux

Linux modules use versioned sonames such as libc.so.6 and libm.so.6. Override paths with UNFFI_*_PATH when a distro stores libraries somewhere unusual.

libc

import { openLibc } from 'unffi/linux/libc'

if (process.platform !== 'linux') process.exit(0)

await using libc = await openLibc()

console.log({
  pid: libc.symbols.getpid(),
  parentPid: libc.symbols.getppid(),
  nativeLength: libc.symbols.strlen('native-unffi'),
  compare: libc.symbols.strcmp('alpha', 'beta'),
})

libm

libm is a separate native math library on many Linux systems.

import { openLibm } from 'unffi/linux/libm'

if (process.platform !== 'linux') process.exit(0)

await using libm = await openLibm()

console.log({
  cos: libm.symbols.cos(Math.PI / 3),
  sin: libm.symbols.sin(Math.PI / 3),
  sqrt: libm.symbols.sqrt(81),
  fabs: libm.symbols.fabs(-123.456),
})

pthread

JavaScript does not expose the native pthread_t for the current thread. Treat it as an opaque integer.

import { openPthread } from 'unffi/linux/pthread'

if (process.platform !== 'linux') process.exit(0)

await using pthread = await openPthread()

const self = pthread.symbols.pthread_self()
console.log({
  pthread: self,
  equalsSelf: pthread.symbols.pthread_equal(self, self) === 1,
})

unistd

import { openUnistd } from 'unffi/linux/unistd'

if (process.platform !== 'linux') process.exit(0)

await using unistd = await openUnistd()

console.log({
  uid: unistd.symbols.getuid(),
  gid: unistd.symbols.getgid(),
  parentPid: unistd.symbols.getppid(),
  rootExists: unistd.symbols.access('/', 0) === 0,
})

access() uses the process' real UID and GID. Containers and user namespaces can make these values look different from a normal shell.

libdl

dlerror() is thread-local loader state. It is useful after a failing manual loader call, but the safe shipped example documents the binding metadata instead of forcing a failure.

import { libdlLibraryPaths, libdlSchema } from 'unffi/linux/libdl'

console.log({
  library: libdlLibraryPaths.candidates[0],
  returns: libdlSchema.dlerror.returns.kind,
})