OMNeT++ 6.2.0 (July 2025)

Highlights of this release are the use of the LLDB debugger inside the IDE, as well as numerous Qtenv improvements: display of documentation brief in module/submodule tooltips, log filtering, and the display of an identicon.

Simulation kernel:

  • Added the WATCH_EXPR() and WATCH_LAMBDA() macros, to allow watching the values of expressions during simulation runtime.
  • cTopology: Added an overload of extractFromNetwork() that takes an std::function, so that it can be used with lambda functions for more flexible network topology extraction.
  • cComponentType: Added getDocumentation() method to access component documentation programmatically, mainly for Qtenv.
  • cAbstractTextFigure: Added getTextExtent() and getFontAscent() methods to improve text measurement capabilities.
  • cEnum: Added resolveName() and getNameForValue() convenience functions to simplify working with enumeration types.
  • Added str() method to RNG classes (cLCG32, cMersenneTwister) to make seed/state information inspectable at runtime.
  • Fixed preDelete() being called multiple times during deletion of a network or compound module, which could lead to unexpected behavior.
  • Match expressions, e.g. cMatchExpression, now accept string literals delimited with single quotes, too. For reference, NED and ini also accept string literals with both single and double quotes.

MSG files, opp_msgtool:

  • Fixed issue #1351 regarding enum declarations not working. Example code that demonstrates the issue:

    enum Foo;  // declaration of an externally defined enum
    class A {
        Foo foo; //Error: unknown type 'Foo' for field 'foo' in 'A'
    }

    This fix allows corresponding workarounds to be removed from INET and other models.

Result Recording:

  • Added record-vector-results, record-scalar-results options that enable/disable writing a scalar/vector file. Previously it was not possible to prevent the creation of .sca / .vec files, because even after disabling the recording of scalar/statistic/vector items using per-object options, empty files (just with the run header and vector declarations) were still created.

Cmdenv:

  • Added -S option that suppresses all stdout output. The existing -s option just made the output less verbose (it is also clarified now in the help).
  • Improved "run info" line printed when running in non-verbose mode (-s option): added run ID, and "#" in front of run number.
  • Added boolean options for finer-grained control of when to log and when not: cmdenv-log-initialization, cmdenv-log-simulation, cmdenv-log-finalization, cmdenv-log-cleanup. Logging during cleanup (network deletion) is now disabled by default.
  • Added cmdenv-progress-updates option, which disables printing periodic progress updates in express mode. Previously, a similar effect could only be achieved by setting the update interval to a very high value.
  • Cmdenv now refuses running an abstract configuration (one marked with abstract=true in the ini file).

Qtenv:

  • Qtenv is now using Qt 6.x. Please note that because of this, the dependencies have changed so you have to run the install.sh script when upgrading to OMNeT++ 6.2.0.

  • Module and channel tooltips now include a brief documentation of that component, with the goal of facilitating understanding of the model's operation for new users. The first paragraph of the component's NED comment is shown. This feature can be turned off in the config dialog ("Show component documentation in tooltips").

  • Added "View NED Type's Source" item to component's context menu. The relevant portion of the NED file is shown in a (read-only) editor window. An important point is that the displayed source includes the component's full NED comment (i.e. its documentation), not just the first paragraph shown in the tooltip.

  • Added simulation identicon and "Show Simulation Info" functionality. The identicon is a programmatically generated geometric pattern that appears at the right side of the toolbar, and its purpose is to help the user tell apart Qtenv windows when several similar simulations open at the same time.

    The identicon is drawn using a "simulation hash" as seed, which includes the OMNeT++ version, the config name and run number, the inifile name, the working directory, the configuration contents, the RNGs, module names, their NED and C++ type names, their parameter names and values, etc.

    There is also a qtenv-identicon-seed config option, which is useful to force identical icons to be used for simulations that would otherwise have different hashes.

    The "Show Simulation Info" functionality displays a report of all values that affect the simulation hash, and more.

  • Added line filtering functionality to the Log inspector. One can specify a string or a regex, and the log window will only display lines that contain the filter string. This "live grep"-like feature vastly improves the usefulness of the log when the user is looking at a certain aspect of the model. An icon on the floating toolbar indicates when a filter is active.

  • Many smaller improvements and bug fixes.

Command-line Tools:

  • opp_featuretool: Improved the detection and handling of inconsistent feature enablements. This includes better validation of the .oppfeatures file, and reporting inconsistent enablements as hard errors (instead of correcting them automatically, which was misleading).

  • opp_charttool: Surrounded chart names with quotes in verbose printouts like "Exporting chart ...", for the reason that chart names may contain spaces and may be quite long, resulting in confusing output. The default resolution of raster output formats was increased from 96 DPI to 300 DPI.

  • opp_python_repl: This is a new tool which starts IPython and imports the omnetpp.repl package. This script is also used by the IDE Terminal View if the INET script is not available.

  • opp_test: Added the %equals, %not-equals, %equals-regex, and %not-equals-regex entry types to complement the %contains family of entry types, and also %no-default-inifile that disables adding _defaults.ini to the simulation command line. Also added the %stacksize directive (default stack size is still 1MB) to allow configuring the stack size for activity-based tests.

  • opp_test: The bulk of the code was factored out into a library under the python folder to allow using its functionality from Python code.

Simulation Launcher/debugging:

  • Switched to using LLDB, the debugger of the LLVM project, for debugging sessions. This change is expected to bring a major improvement in debugging experience, as GDB was increasingly falling behind in terms of performance and platform support. To support LLDB, we integrated the LSP4E project's DAP (Debug Adapter Protocol) component, a more modern and extensible debugging infrastructure. The LSP4E DAP debugger also replaces LLDBMI2, our earlier attempt to replace GDB with LLDB. The LLDB debugger is launched via the opp_dbgdap helper script.
  • The Simulation Launcher now converts library paths to absolute path when specifying the -l option to the simulation. Using absolute path prevents issues with LLDB not being able to set breakpoints in dynamically loaded shared libs. This issue is present in LLDB 19 on Linux. See: llvm/llvm-project#124761
  • In the Simulation Launcher, changed the variable substitution in the simulation launch command line arguments to allow missing variables. References to variables unknown to the IDE are now left unchanged. This allows arguments like --output-scalar-file=${resultdir}/foo.sca to be specified to the simulation program (${resultdir} is meant to be processed by the simulation program, not the IDE).
  • Enhanced OMNeT++-specific LLDB formatters (omnetpp.lldb.formatters.omnetpp)
  • Switch to the Debug perspective when the IDE attaches to a simulation process in response to the simulation process invoking the IDE with an omnetpp:// launcher URL.

Python REPL:

  • Added a Python REPL to the Terminal view. To open it, click the "Open Terminal" button in the view and select "OMNeT++ Python REPL". The REPL opens with the omnetpp libraries imported, and you can call read_result_files(), run_simulations(), etc. You can use opp_python_repl from the command line to start the Python REPL.

NED editor:

  • Ctrl+clicking NED type names within comments and string constants now work.
  • The editor now removes trailing spaces from NED files on Save.
  • Fixed wrong module class name resolution in NED editor (Ctrl+Tab did not always go to the C++ class that implements that type), and several other issues.
  • Significantly improved the usability of the "NED Inheritance" view:
    • only show full subtype hierarchy of selected type, not of its root type
    • show inheritance chain of selected element
    • reveal and select the input type (and try revealing the root too)
    • child nodes were not sorted, making it hard to locate items
    • it only showed content when the cursor was positioned inside the component definition in the NED file

Analysis Tool:

  • Added unit conversion support for various chart types, including vector, histogram, box-whiskers and bar charts. It is now possible to specify a measurement unit (e.g. kB, Mbps, us) for axes. (Until now, the base unit was used unless the user manually customized the chart.) If no unit is specified in the dialog, the most convenient unit is chosen automatically, based on the range of the actual values displayed.
  • Added support for measuring the horizontal and vertical distances between two points on a plot. The delta measurement feature is activated using keyboard shortcuts when the mouse cursor is over the plot area. The "A" key selects the start point, the "D" selects the end point and shows the distances; the "S" key shows the horizontal and vertical deltas for a line segment; "X" clears the markers.
  • Added "Zoom to Fit Data" action to native line plots, without also including the origin. "Zoom to Fit" was renamed to "Restore Original View".
  • Recognizing that plot navigation gestures (e.g. keyboard and mouse bindings for zooming in and out) are not so easy to remember, we added a navigation help button to plot toolbars. This opens the relevant section of the User Guide in the Help view.
  • Significantly improved "Export Charts" dialog:
    • Clarify that charts must be designated for export by ticking their checkboxes, not by making a list selection
    • Improved hint about emulating native widgets with Matplotlib (e.g. replaced "" mark with "emulated" in the tree)
    • Add "Set Export Size" button.
    • Show plot size in pixels as well as inches before export.
    • Change the default chart export DPI from 96 to 300.
  • "Save Image" dialog: Make the note about image formats more noticeable. Save chart image as PNG by default.
  • Several small bug fixes and improvements, such as better colors in dark mode at certain places, and making zooming and panning affect only the X axis on enum strips.
  • Allow working with output vectors with more items than 2^31.

IDE Misc:

  • Project Features: Fix bug introduced in the previous release (version 6.1) when the IDE does not write out the .nedexclusions file when the feature enablements changed.
  • Sequence Chart: To speed up parsing eventlog files from Java, replaced the C++ LineTokenizer (accessed via JNI) with a pure Java variant. This makes parsing of eventlog entries several times faster because the C++/Java bridging to LineTokenizer is slow. The measurements were done using a Java profiler.
  • Fixed launching simulations from the IDE, sometimes there was an exception related to immutable collection.
  • Ini file form-based editor: fix wrong colors in dark mode (#1356)
  • Associate ".d" files with the normal Eclipse text editor. They are dependency files, generated by our makefiles in the out/ dirs. Without this change, they show up with an ugly oversized green icon in the Open Resource dialog (observed on the Ubuntu 24.04 Gnome desktop).
  • The IDE now writes its crash log into the XDG_STATE_HOME folder by default, i.e. to $HOME/.local/state/omnetpp/ide-error.log. This file can be checked if the IDE does not start or crashes. (The normal Eclipse log is still written into the .metadata folder in the workspace.)
  • Upgraded to Eclipse 2025-06.

Python libraries:

  • requirements.txt: Added IPython as a dependency (as the IDE now has an IPython console).

  • requirements.txt: Accept NumPy 2.x as well as 1.x as dependency

  • requirements.txt: Use packaging instead of setuptools to parse version numbers because setuptools got deprecated.

  • Added the opp_python_repl command and the omnetpp.repl package which starts an interactive IPython interpreter with the omnetpp packages loaded.

  • Added the omnetpp.test package that contains the functionality of the opp_test tool. This allows using the test code both as a python library and as a standalone script.

  • omnetpp.scave: Change the default chart export DPI from 96 to 300.

  • omnetpp.scave: Implemented unit conversion support for vector, histogram, bar and box-whiskers charts. This affects the operation of plot_vectors() and similar plot_*(), and postconfigure_plot() functions.

  • Many bug fixes in the omnetpp.scave library.

User Guide:

  • The "Qtenv" chapter was significantly revised and expanded.
  • In the "Result Analysis" chapter, the "Plot Navigation" section was expanded to include all possible gestures in all the modes for both types of plots (native/matplotlib), and also mention the function of the X and Y keys.

Install Guide:

  • Installation instructions got simplified and updated.
  • Added a new chapter for ArchLinux.
  • Expanded Windows installation instructions to cover instructions for installing in Windows Subsystem for Linux (WSL).
  • Added instructions to use opp_env as the recommended installation method.

Tests:

  • New tests

Build:

  • On Windows, the bundled MSYS2 installation is upgraded to the 2025-05-23 snapshot.

See ChangeLogs in individual folders for details.

Bugs fixed: https://github.com/omnetpp/omnetpp/issues?q=is%3Aissue+is%3Aclosed+milestone%3A6.2


What's New in OMNEST 6.1.0