Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

1.1.0 - 2026-05-09

iommap:region_binary/3 returns a refcounted resource binary that points directly into the mapped region, with no data copy. Intended for hot zero-copy hand-off paths.

The NIF resource layout was split into a mapping resource (owns the mmap region and fd) and a handle resource (owns the BEAM handle term and one reference to the mapping). close/1 releases the handle's reference to the mapping; munmap and close(fd) are deferred until any outstanding region binaries derived from that mapping are also garbage collected. Existing API behaviour is unchanged.
truncate/2 now allocates a fresh mapping (with a duplicated fd) and atomically swaps it into the handle. The previous mapping remains alive for outstanding region binaries.

region_binary/3 is unsafe against external truncation that shrinks past a binary's range. Use pread/3 when safety against external mutation is required.

Initial release of iommap
Dirty NIF I/O schedulers for all I/O operations
Cross-platform memory-mapped file I/O for Erlang/OTP
Support for Linux, macOS, FreeBSD, and OpenBSD
Core operations: open/2,3, close/1, pread/3, pwrite/3
Synchronization: sync/1,2 with sync/async modes
File management: truncate/2, position/1
Memory advice: advise/4 with madvise hints
Thread-safe implementation using pthread rwlocks
SIGBUS protection for external file truncation
Platform-specific optimizations:
- MAP_POPULATE support on Linux
- MAP_NOCACHE support on macOS
- fallocate on Linux, posix_fallocate on BSD
Comprehensive test suite with 20 tests
CI pipeline for all supported platforms