std/sys/process

#cwd

Absolute path of the process's current working directory.

"" when the platform will not answer — the cwd was deleted out from
under the process, or its path is not representable. Not a throws:
this is read by a diagnostic or a path join, and forcing a try/catch
around a primitive that essentially never fails would cost every call
site more than the case is worth.

#chdir

Change the process's working directory to path.

The platform answers only whether it moved, so the raise says what was
asked rather than why it was refused: the reasons — no such directory,
not a directory, no permission to enter it — are not distinguished by
the call, and inventing one of them would be worse than naming none.

#argc

Number of command-line arguments, including the program name at index 0.

#__argAt

The argument at index, or "" when there is none or it outruns the
scratch buffer. Private: argAt is the checked form and is what
source calls, so the sentinel never reaches a caller who did not ask
for it.

#argAt

The argument at index in argv.

#programName

The program name — argv[0], or "" where the platform supplied
none.

Non-throwing where argAt(0) throws: a usage banner and a diagnostic
prefix are what read it, and neither has a catch to offer.

#getEnv

Read environment variable key.

#hasEnv

True iff environment variable key is present (even if empty).

#setEnv

Set environment variable key to value; inherited by child processes.

Refused once the program has created a thread, and silently: a
reader holds a pointer into the environment table and a write frees
what it replaces, with no lock either side could join. Set what a
program needs before it spawns.

#unsetEnv

Remove environment variable key from this process's environment.
Refused after a thread exists, for the reason setEnv gives.

#envOrDefault

Read environment variable key, falling back when it is unset OR set
to the empty string.

The two cases are indistinguishable through getEnv, and a caller
that wants a fallback wants it for both — which is what saves an
if (!hasEnv("X")) guard at every call site.

#__getProcessId

The unix spelling of this process's own id.

#__getParentProcessId

The unix spelling of the id of the process that started this one.

#__getProcessId

The Windows CRT's spelling of the same query.

#pid

This process's own process ID.

#parentPid

The parent process's ID, or 0 where the platform keeps none a
process can read.

Windows is that case: the id of the creating process lives in a
structure only the snapshot API walks, and that walk names a reused
id as readily as a live one — a parent that has exited leaves its
number to somebody else. 0 is the honest answer, not a placeholder
for one that could be looked up.

#parentPid

See the unix arm: this platform keeps no readable link to a parent.

#abort

Abnormally terminate the process by raising SIGABRT.

#constructor

Begin building a command.

#addArg

#setDirectory

#setEnv

#inheritIO

#start

#waitFor

Wait until the child exits. A task parks and its carrier keeps running
the tasks that share it. A second waitFor from another task waits for
the first to record the status and answers the same one.

#exitValue

#isAlive

#destroy

#pid

#getStdout

#getStderr

#close

close() aliases destroy() so a try-resources binding can clean
up a child process on scope exit. Pure Axle over destroy: the
two are the same act, and one of them being a second FFI symbol
would be a second place for that to stop being true.