Changes for version 1.14 - 2026-05-22
- Modify remove() to properly catch a non "0 but true" case when trying to destroy segments and semaphores so warnings are displayed properly
- remove() now leaves the global and process registers intact if the destroy operation fails
- Rename _mg_tie() to _magic_tie()
- Rename _is_kid() to _is_child()
- In IPC::SharedMem, removed leading underscore from object attributes
- Parameter list in IPC::SharedMem::new() is now in the form of a hash
- Code refactoring in IPC::SharedMem
- Add POD for IPC::SharedMem
- SharedMem::remove() now returns 1 on '0 but true' and 0 otherwise that was preventing matches from happening, and broke JSON
- ipcs() now ignores lines that don't include an actual key
- Add data() method to SharedMem. This strips off the NULL pad bytes from shmread()
- Added key_hex() to SharedMem. Will allow for easier troubleshooting when using ipcs (closes #32)
- Added SharedMem::stat(); returns a new object that contains the related info about the actual shared memory segment
- Fixes #49; Logic error from old implementation of JSON
- Fixes #47; Clean up broken code in old _decode_json()
- Fixes #41; JSON serializer not handling nested data structures properly
- Closes #52; Add tests and POD for SharedMem::stat struct methods
- Added SharedMem::stats(), return an href of all segment stats
- Closes #48; All tests now run unconditionally; there is no more CI_TESTING flag required
- Greatly simplify the FIRSTKEY and NEXTKEY shared hash ops; removed the _iterating flag complexity and replaced it with an _hkey_list instead
- Fixes #38; Fixed issue where the global_register was not being populated if a data access hadn't happened yet, causing leaked segments upon cleanup. This fix eliminated the weird 'Dumper' hack
- Add new scripts/flush_ipc.sh script that cleans out all segments and semaphores from the system for the current user
- Closes #28; Add link to Script::Singleton in singleton() POD
- Closes #24; lock() now allows a cref parameter. If a LOCK_EX lock can be acquired, we will set the lock, execute the subroutine, then release the lock
- 'tidy' attribute now defaults to true
- All unit tests do a check for leaked segments and semaphores at their conclusion. Also, when running 'make test' it compares the numbers before and after and doubly makes sure there are no leaks
- Closes #51; Better document that the 'size' attribute is for each segment, and not the overall size of all the data. Also emphasize that each nested data structure requires an additional segment, they aren't all stashed into a single one
- Added uuid(), sets an internal UUID for each tied object (primarily used for troubleshooting)
- Fixes #50; Added enforced locking, with optional warning
- Correct five areas in clean/delete routines where segments may have been able to leak
- Removed redundant _global_register checks in STORE, FETCH, PUSH; _tie() already registers unconditionally
- Add ref() check before _is_child(); skips the function call reftype() entirely for plain scalar values in FETCH, CLEAR, and DELETE
- Add ref() check before _need_tie(); same pattern in all three STORE branches
- _type_int numeric dispatch; string eq comparisons on every operation replaced with == against integer constants in STORE, FETCH, and CLEAR
- Major POD enhancements/cleanup
- Renamed ipcs() to seg_count() as it's far more explanatory
- Add new method sysv_info() which if the system provides it, retrieves all information related to the SYSV infrastructure (limits etc)
- Closes #45; We now accept a hex-based value as the key
- Added shm_segments(); fetches raw data about all segments that had been created by this distribution
- Added unknown_segments(); returns an aref of all segment keys (in hex string format) for segments we've created but are no longer registered to any known process
- Closes #39; remove() now accepts a key, and can remove the segment and semaphores related to that key, even if it isn't related to this distribution
- Updated CI so we get a test run on an i386 Ubuntu container to test 32-bit platforms
- Fix issue when using JSON serializer where it wasn't properly handling scalar references properly (eg. creating a tie with a hashref)
- Enhanced much of the test suite to test both Storable and JSON serializers
- Much work in order to add provisions so that shm counting and tracking works on FreeBSD
- Add FreeBSD VM config and unit test runner in ci/ dir
- Removed the archaic _debug() and _trace functions
- Enhanced 'protected' segments; we now use a semaphore to mark a segment as protected (SEM_PROTECTED), and all processes that load this segment will inherit the protected status
- Add sem_map(); outputs a text representation of the segment/semaphore mappings
- Added consistent naming for all four semaphores: SEM_EXISTS, SEM_READERS, SEM_WRITERS, and SEM_PROTECTED
- Default serializer now JSON; Added check for backwards compatibility that if JSON _decode() fails, we then attempt a Storable _thaw()
- Added sem_count(); behaves like seg_count() but for semaphores. Also updated tests to ensure no straggling semaphores are left behind
- All LOCK_EX and LOCK_SH locks are now applied to all child segments when the lock is first instantiated on the tied object. Both of them are rolled out in reverse order from the lowest-level child upwards when the lock is released
- New attributes for updated locking mechanisms: enforced_write_locking, enforced_read_locking, violated_write_lock_warn and violated_read_lock_warn. All enabled by default
- Fixes #11; On non-English locales on perl 5.20 and below, checking $! for strings in certain cases was failing and sending code down the wrong path. The fix was to replace the comparisons with $!{ERRNO_CONST} variables instead (eg. $!{EEXIST}, $!{ENOMEM}, $!{ENOSPC}) which are locale-independent
- Add Solaris (including OmniOS/illumos) support for shm_segments(), seg_map(), and SharedMem stat()/stats() methods by providing Solaris-specific shmid_ds unpack templates
- Add explicit use Errno so that $!{ENOMEM} and $!{EEXIST} checks work reliably on all platforms (Solaris Perl builds did not populate these keys in the %! tied hash without the module loaded)
- Complete VM unit testing framework with scripts and README for FreeBSD, Linux i386 and Solaris (32 and 64 bit)
- Replace regex-based null-byte stripping in SharedMem::data() with more efficient index+substr
- SharedMem::stats() now calls stat() once and reuses it, avoiding 11 redundant shmctl(IPC_STAT) syscalls
- _encode_json_prepare() now short-circuits for structures with no IPC::Shareable child refs, avoiding a full hash/array copy on every encode
- _decode_json_restore() hoists ref($prev) checks outside hot loop
- Added XS implementation of _is_child() for faster child-knot detection; falls back to pure Perl _is_child_pp() if the compiled XS can't be loaded. The XS function _is_child_xs inspects SV magic directly in C, avoiding Scalar::Util::reftype, tied(), and ref() calls
- Added t/75-is_child_xs.t to test both XS and pure-Perl _is_child paths
- Added IPC_SHAREABLE_NO_XS env var to force pure-Perl mode for verifying operation on systems without a C compiler
- Eliminated redundant second ipcs -m shell-out in seg_map(); get id mapping from shm_segments() result instead
- Replaced all backtick shell-outs with open('-|', @cmd) pipe-open to bypass /bin/sh and halve the fork count
- Rewrote _lock_children() from recursive to iterative (manual stack) to eliminate Perl call-stack overhead on deeply nested structures; simplified interface returns an arrayref instead of passing accumulator/seen refs
- Fix STORE child-segment leak: old child references were silently discarded without removing shm segments/semaphores. STORE now calls _remove_child() before overwriting. Extracted the common pattern into _remove_child() to deduplicate across DELETE, CLEAR, and STORE.
- Remove the 'tidy' attribute and _reset_segment() internals. The STORE fix made _reset_segment() a no-op that only produced double-removal warnings.
- Fix t/25-fetch_read_warn.t pipe synchronization so the parent blocks until the child confirms LOCK_EX, instead of a blind sleep
- shm_segments() now probes the 14-byte 'IPC::Shareable' tag before pulling the full segment into Perl, avoiding gigabyte allocations for foreign segs
- Drop unconditional use-time srand(); _shm_key_rand collisions are already caught by the IPC_EXCL re-check loop, so reseeding callers' RNG is needless
- Remove redundant Data::Dumper imports from Shareable.pm and SharedMem.pm
- Fix _shm_key() off-by-one: overflow-correction now triggers on crc32 == MAX_KEY_INT_SIZE, making the post-subtraction key==0 croak actually reachable
- Test coverage additions: unknown_segments() via fork+exit, sysv_info() on Solaris, JSON->Storable carp format, both write-lock flags disabled, _shm_key() key==0 croak (Mock::Sub on crc32), IPC_PRIVATE + JSON nested tie, STORE scalar-ref over previous \$undef
- Fix t/73-internal.t cross-version: qr// reftype differs between 5.10 and 5.12+, so use a CODE ref to exercise the _encode_json_prepare fallthrough
- Bump prereq of Test::More to 0.98 due to 5.10.1 using 0.94 by default
Documentation
Modules
Use shared memory backed variables across processes
Allows access to a shared memory segment via an object oriented interface.
Provides
in lib/IPC/Shareable/SharedMem.pm