Project

Release notes

This page lists the changes in each release of FairMQ, the newest release first. The source of each section is the GitHub release and the Git history. Breaking marks a change that can stop your code or your build, or that stops devices of the new and of an older version from working together in one shared memory session. Read these items before you update.

FairMQ does not keep ABI compatibility between releases. After each update, build your devices again. See Install layout.

Mixed versions

With the shmem transport, use the same FairMQ version for all devices of a session. With the zeromq transport, the FairMQ version does not change the bytes on the connection.

zeromq. The transport sends a message as one ZeroMQ frame that contains only your data. It sends a multipart message as a ZeroMQ multipart message with one frame for each part (fairmq/zeromq/Socket.h). FairMQ adds no header and no version number. The compatibility of different ZeroMQ versions is ZeroMQ behavior.

shmem. The transport keeps the data in shared memory and sends only metadata through ZeroMQ. The receiver copies the bytes of the metadata into its own MetaHeader (fairmq/shmem/Socket.h). All devices of a session also use the same management segment, managed segments and regions. The metadata and the structures in shared memory contain no version number, and the transport does not compare the versions of the devices. These releases changed the data that the devices of a session share:

Release	Change
v1.6.0	The metadata message of a multipart message starts with the number of parts, a `size_t`. Before, the receiver calculated the number from the message size. Since v1.6.0, the sender pads each metadata message to `--shm-metadata-msg-size` (default 0: no padding). A receiver of v1.5.x accepts a single-part metadata message only with the exact size of one `MetaHeader`, and a multipart metadata message only with a multiple of this size. A receiver of v1.6.0 or later reads the first `size_t` of a multipart metadata message of v1.5.x as the number of parts.
v1.8.1	The entry of a region in the management segment (`RegionInfo`) has the new field `fRCSegmentSize`. The reference count of a copied region message is in the reference count segment of the region. Before, it was in a managed segment.
v1.9.0	The pool of the reference counts in the reference count segment of a region has a different type of Boost.Interprocess: `node_allocator` instead of `adaptive_pool`.

The fields of MetaHeader are the same from v1.5.0 to dev. The changes on dev after v1.11.0 do not change the metadata or the structures in shared memory.

The segments and the regions are objects of Boost.Interprocess. Their layout in memory is Boost behavior, and FairMQ does not check the Boost version of the other devices. To see the versions of a device, read its log. At start, a device program with fairmq/runDevice.h logs a logo with version and the Git version of FairMQ (severity info). The shmem transport logs Transport: Using ZeroMQ (…) & boost::interprocess (…) with the two versions (severity debug).

Unreleased on dev

These changes are on the branch dev after v1.11.0. They are not in a release yet. All changes.

New: fair::mq::tools::execute() has an overload with a timeout of type std::chrono::milliseconds. It stops the child process with SIGKILL after the timeout. The old overload has no limit. See execute() and Process.h.
Fixed: shmem: a message that received a block of a region, was rebuilt, and then received a block of a second region released this block to the first region. Now each block goes back to its own region.
Fixed: shmem: a thread that creates a region and a thread that opens a region in the same session can no longer deadlock.
Fixed: shmem: a region callback that calls the transport while the region is removed no longer blocks. Before, this blocked all processes of the session.
Fixed: shmem: the removal of a region took a minimum of 500 ms. Now the thread that sends the acknowledgements stops without this wait.
Fixed: zeromq and shmem: a socket stops its socket monitor before it closes. This removes a memory leak of monitor events (#463).
Tests: many new tests for the state machine, the device, the channels, the properties, the tools and the shmem monitor. Many tests run once for each transport, and the test name ends with the transport. Multi-process tests use one test harness. See Contributing and Add a test.
CI: the tests run in parallel. The job asan+lsan+ubsan builds with FAIRMQ_DEBUG_MODE=ON.
Docs: this documentation site is new.
Breaking Build: the CMake option BUILD_DOCS and the package component docs are removed. find_package(FairMQ COMPONENTS docs) fails.
Build: the bundled GoogleTest is updated to commit a8380b0.

v1.11.0

Released 2026-06-10 · GitHub release · All changes

New: shmem: the side-channel metadata API. A device can send the metadata of a shmem message in its own format. A device of the same session then reads the data in place (#555). See Out-of-band buffers.
Fixed: shmem: a failed region lookup stayed in the region cache, so all later lookups of this region failed also. Now a later lookup tries again.
Fixed: fair::mq::tools::execute(): calls from several threads write the captured output one line at a time. Before, this was a data race.
Changed: a channel compiles the regular expression for the validation of its name only once.
Build: .clang-tidy enables only a selected set of checks, and the code has no warnings for these checks. See Code style.
Build: the new CMake variable FAIRMQ_TEST_LD_LIBRARY_PATH adds a directory to LD_LIBRARY_PATH of each test. See Other variables.
Build: linker flags from the CMake command line no longer break the link command.
CI: the job tsan uses GCC with an instrumented libzmq and libstdc++. The job static-analysis fails on each warning. The jobs use ccache and a higher limit for locked memory.
Build: the bundled GoogleTest is updated to commit 9156d4c.

v1.10.1

Released 2026-01-05 · GitHub release · All changes

Fixed: FairMQ builds with Boost 1.89 and later. It uses the Boost.Process v1 API from boost/process/v1.hpp (#538).
Build: CMake stops with an error for Boost 1.88. This Boost version has no Boost.Process v1 API. Use Boost 1.87 or earlier, or 1.89 or later.
CI: the CI moves from Jenkins to GitHub Actions. Spack installs the dependencies. The jobs build with GCC 12 to 15 and with Boost 1.87, and run the sanitizers and the static analysis.

v1.10.0

Released 2025-06-13 · GitHub release · All changes

Breaking Changed: fair::mq::pmr is now an alias of std::pmr. Before, it was an alias of boost::container::pmr (#532). Code that uses Boost memory resources with FairMQ must change to std::pmr. See Use std::pmr memory resources.

v1.9.2

Released 2025-03-17 · GitHub release · All changes

Changed: cmake --install also installs the shmem headers Manager.h, Message.h, Poller.h, Socket.h, TransportFactory.h and UnmanagedRegionImpl.h in include/fairmq/shmem/.

v1.9.1

Released 2025-01-23 · GitHub release · All changes

Changed: some methods of EventManager are compiled in the library and not in the header.

v1.9.0

Released 2025-01-09 · GitHub release · All changes

Breaking Changed: the headers Device.h, Channel.h, Message.h, TransportFactory.h and UnmanagedRegion.h include fairmq/TransportEnum.h and no longer fairmq/Transports.h (#519). If your code uses TransportName(), TransportType(), TransportError or operator<< for Transport, include fairmq/Transports.h.
New: the control mode --control none. The control plugin does not take the controller role, so another plugin or your code must change the states (#503). See Control modes.
Fixed: shmem: the reference count segment of the regions had a low performance (#501).
Breaking Changed: shmem: the reference counts of copied region messages use the pool type node_allocator instead of adaptive_pool (commit 0e221b28). Do not copy region messages in a session with devices of v1.8.x and of v1.9.0 or later. See Mixed versions.
Changed: the multipart Send() and Receive() of a socket take a Parts::container (#507). This type is std::vector<MessagePtr>, as before.
Changed: ProgOptions::SetProperty() for int and std::string is compiled in the library and not in the header (#518).
Build: FairMQ builds with Boost 1.87 (#521).
Build: the project uses all CMake policies up to CMake 3.30 (#512).
CI: a workflow checks that codemeta.json and .zenodo.json agree with AUTHORS and CONTRIBUTORS (#498). Dependabot updates the GitHub Actions and the Git submodules.
Build: the bundled GoogleTest is updated to commit 7d76a23.

v1.8.4

Released 2023-11-29 · GitHub release · All changes

Changed: shmem: if RegionConfig::rcSegmentSize is 0, a region uses the reference counting from before v1.8.1 (#493). See RegionConfig.

v1.8.3

Released 2023-11-24 · GitHub release · All changes

Fixed: shmem: the creation of a reference count segment did not use the stored configuration of the region (#492).

v1.8.2

Released 2023-11-15 · GitHub release · All changes

Changed: shmem: the default size of the reference count segment increases to 100,000,000 bytes (#490).
Changed: shmem: the error message is better when the reference count segment has no free space. The transport throws RefCountBadAlloc (#490).

v1.8.1

Released 2023-11-10 · GitHub release · All changes

Changed: shmem: the reference counts of region messages are in a pool in a dedicated segment. RegionConfig::rcSegmentSize sets the size of this segment (#484). See Copies of region messages.
Breaking Changed: shmem: the entry of a region in the management segment has a new field. Do not use devices of v1.8.0 or earlier in a session with devices of v1.8.1 or later. See Mixed versions.
Changed: shmem: the Message class is smaller (#485). Message::SetUsedSize() has an optional alignment argument.
Fixed: the state machine protects the containers of its subscriptions with a mutex.
Fixed: tests no longer use the same addresses.

v1.8.0

Released 2023-09-06 · GitHub release · All changes

New: StateMachine::SubscribeToStateChange() calls the callbacks in the order of the number at the start of their key (#481). See SubscribeToStateChange().

v1.7.0

Released 2023-06-26 · GitHub release · All changes

New: the CMake variable FAIRMQ_CHANNEL_DEFAULT_AUTOBIND sets the default of the channel property autoBind (#475). See Compile definitions.

v1.6.0

Released 2023-06-13 · GitHub release · All changes

New: the option --shm-metadata-msg-size sets the size of the zeromq message that carries the shmem metadata (#435). See Options.
Breaking Changed: shmem: the metadata message of a multipart message starts with the number of parts. Devices of v1.6.0 or later and devices of v1.5.x cannot exchange multipart shmem messages. See Mixed versions.
Fixed: the compiler warning -Wunqualified-std-cast-call.

v1.5.0

Released 2023-03-07 · GitHub release · All changes

Breaking Removed: the components sdk, sdk_commands and dds_plugin (discussion #392). They moved to the ODC project.
Breaking Changed: FairMQ is one shared library again. The exported targets FairMQ::Tools and FairMQ::StateMachine are removed. Link FairMQ::FairMQ.
Breaking Changed: the default of --shm-monitor is false. By default, the shmem transport does not start the monitor daemon.
Breaking Removed: Device::TransitionTo(), without a replacement.
Breaking Removed: the experimental ofi transport and the experimental PMIx plugin.
Breaking Changed: FairMQ uses std::filesystem. To use Boost.Filesystem, set -DFAIRMQ_HAS_STD_FILESYSTEM=0. The default is 1 for GCC 9 or later and Clang 9 or later.
Deprecated: the headers and the type names without a namespace, for example FairMQDevice.h and FairMQDevice (discussion #423). See Move from the FairMQ* names.
Deprecated: Device::fChannels.
New: library and plugin files have kebab-case names, for example libfairmq-plugin-myplugin.so. The old names, for example libFairMQPlugin_myplugin.so, continue to work.
New: Device::ChangeState() is [[nodiscard]]. Device::ChangeStateOrThrow() throws an exception if the transition is not possible (#441). See ChangeStateOrThrow().
New: operator<< for fair::mq::Channel.
New: the example custom-controller, with a controller plugin that is compiled into the device.
Changed: the ABI version is equal to the release version. FairMQ does not keep ABI compatibility between releases.
Changed: the build types Release and RelWithDebInfo compile with -O3 instead of -O2.
Fixed: zeromq: messages of the monitor socket leaked.
Fixed: the device protects its container of transports with a mutex.

Older releases

The releases page on GitHub lists all releases, also v1.4.56 and earlier.

Install: install a release.
Contributing: the branches and the release tags.
Move from the FairMQ* names: replace the names that v1.5.0 deprecates.