Standard Library Reference

Zero's standard library is pay-as-used and capability-aware. Importing memory helpers does not pull in hosted filesystem helpers.

Hosted APIs report their target requirements in zero graph and zero size.

Runnable modules:

std.mem: spans, byte equality, copy/fill, fixed-buffer allocators, byte buffers, and arena-style reset helpers.
std.io: buffered reader/writer metadata and byte copy helpers over caller-owned storage.
std.args: hosted process argument count and indexed lookup.
std.env: hosted environment variable lookup.
std.fs: hosted file lifecycle helpers, owned file handles, byte reads/writes, remove, rename, and close.
std.path: fixed-buffer path joining.
std.parse: allocation-free ASCII scanners and unsigned integer parsers.
std.codec: byte-oriented integer encoding, varint length, and CRC-32 helpers.
std.json: validation, streaming token counts, explicit-allocator parsing, and caller-buffer string writing.
std.time: duration math plus target-gated monotonic and wall-clock helpers.
std.rand: explicit deterministic random sources and target entropy helpers.
std.proc: host process status helpers behind the process capability.
std.crypto: small hash, keyed hash, constant-time equality, and entropy helpers.
std.net: network capability metadata and bootstrap connection/listener handles.
std.http: HTTP method, body-length, client/server metadata, and TLS-boundary helpers.

Each module page documents target support, allocation behavior, error behavior, ownership notes, and runnable examples.

Use the CLI to inspect what a program actually retains:

Command	Shows
`zero graph --json <input>`	Required capabilities and imported helpers.
`zero size --json <input>`	Helper metadata and retained helper cost.
`zero mem --json <input>`	`memoryBudgets`, `allocatorFacts`, `allocationInstrumentation`, and `collectionFacts`.

The stdlibHelpers and usedStdlibHelpers JSON entries include module, effects, allocationBehavior, targetSupport, errorBehavior, ownershipNotes, example, and apiStability for each public helper.

Metadata Contract

Public standard library symbols document the fields agents need to call them safely:

symbol: std.fs.readAllOrRaise
effects: fs
allocation behavior: caller allocator
target support: host
error behavior: raises { NotFound, TooLarge, Io }
ownership notes: returns owned<ByteBuf>
example: examples/readall-cli/

Module pages may group related symbols when their metadata is identical.

Keep these labels visible: effects, allocation behavior, target support, error behavior, ownership notes, and example.