zlibVersion
Returns the linked library's release string.
Full chapter and shared rules ↗767fa1407a7fe3d1 · Source at the matching commit ↗Read the function’s preconditions and results first. Expand the shared rules below for buffer and ownership requirements used throughout this API group.
const char * ZEXPORT zlibVersion(void);
Returns the linked library's release string.
Domain Full type domain.
Pre Full type domain; no arguments or caller state are required.
Post Returns a non-NULL pointer to NUL-terminated ZLIB_VERSION (1.3.2.1-motley).
Effects Read-only. The result is borrowed immutable static storage; the caller must neither write it nor free it. No allocation or heap change occurs.
Shared conditions and scope
API manual · Shared stream rules · Checksums
Use the buffer utilities when the complete input and output capacity are known at the call. They manage a temporary stream internally. Use the stream pages when you need incremental I/O, a different wrapper, a dictionary or explicit flush boundaries.
| Task | Entries |
|---|---|
| Compress a buffer | Choose a level, default level, size the destination |
| Decompress a buffer | Report input consumed, output only |
| Inspect the library | Version, compile flags, error text |
The focused contracts follow compress.c, uncompr.c, zutil.c and zlib.h in the default
LP64 Linux build. _z forms use z_size_t; plain forms use uLong. Both are 64-bit here.
Source readings are to confirm by proof. They do not narrow the registered targets in
Utilities.lean and
Queries.lean.
Calls.lean fixes translated arguments and results.
See contract conventions for domain/effect labels and
progress for proof status and remaining work.
The buffer utilities create and release a local stream with the zlib wrapper and default settings.
flowchart LR
B["compressBound"] --> C["compress / compress2"]
C --> Z["zlib stream"] --> U["uncompress / uncompress2"]
U --> D["decoded bytes"]
Common conventions
For buffer calls, the domain is restricted to valid memory: non-NULL sources cover the stated readable input; non-NULL destinations cover the stated writable capacity. Non-NULL length pointers name readable, writable scalar cells. Input, output and length cells are separate, including the two length cells when both occur. The caller keeps those objects live and does not modify them during the call. Each entry states its allowed NULL cases. Other invalid pointers are outside this scope. Decompression error handling needs no valid compressed-data assumption.
Common effects. Every in-scope call terminates without a fault. Buffer calls preserve input and memory outside the output and length cells. They write at most the original capacity. All internal allocations are released before return, including on allocation failure; no local stream or owned allocation is returned. Pointer-valued queries return borrowed immutable storage. These are contract requirements, not claims that the implementation proofs are complete.
Formal contract
ZlibF.Spec.Public.Goal.zlibVersion
Proof status: Registered proof · Evidence and remaining work
/-- `const char *zlibVersion(void)`.
Every heap returns the pinned header's version string, as static read-only storage.
The call terminates without a fault, allocates nothing and changes no heap observation. -/
def Goal.zlibVersion : Prop :=
∀ h : Heap, ∃ p,
C.run Zlib.Zutil.zlibVersion h = .ok (p, h) ∧ StaticString h p ZLIB_VERSION