Core Engine The core engine module, including lifecycle management, simulation options, and shared utilities.

Files
file	charconv_compat.hpp
	Portable from_chars for floating-point types.
file	DateTime.hpp
	DateTime utility functions — numerically identical to legacy datetime.c.
file	InpWriter.cpp
	Comprehensive .inp serialisation — round-trip identical output.
file	InpWriter.hpp
	Write a SimulationContext to a SWMM .inp file.
file	InterfaceFile.cpp
	Routing interface file — coupling between separate SWMM simulations.
file	InterfaceFile.hpp
	Routing interface file — coupling between separate SWMM simulations.
file	SimulationContext.hpp
	The central, reentrant simulation context for the new engine.
file	SpatialFrame.hpp
	Spatial frame — CRS specification and coordinate data for nodes/links.
file	UnitConversion.cpp
	Global unit conversion — matching legacy SWMM UCF().
file	UnitConversion.hpp
	Global unit conversion factors — matching legacy SWMM Ucf[]/Qcf[].
file	UserFlags.hpp
	User-defined model flags (InfoWorks ICM-style, two-section design).

Classes
struct	openswmm::PluginSpec
	One plugin entry from the [PLUGINS] section. More...
struct	openswmm::SimulationContext
	Central, reentrant simulation context. More...
struct	openswmm::SimulationOptions
	All SWMM simulation options parsed from [OPTIONS] section. More...
class	openswmm::ICouplingPoint
	Abstract coupling point between a 1D SWMM object and a 2D mesh cell. More...
struct	openswmm::SpatialFrame
	Spatial frame containing CRS and georeferenced coordinates. More...
struct	openswmm::UserFlagDef
	Schema entry for a single user-defined flag. More...
struct	openswmm::UserFlagAssignment
	A (object_type, object_name, flag_name) → value assignment. More...
class	openswmm::UserFlags
	Stores the full user-flags data: schema definitions + per-object values. More...

Typedefs
using	openswmm::UserFlagValue = std::variant< bool, int, double, std::string >
	A concrete flag value assigned to a specific object.

Enumerations
enum class	openswmm::EngineState : int32_t {   openswmm::EngineState::CREATED = 0 ,   openswmm::EngineState::OPENED = 1 ,   openswmm::EngineState::INITIALIZED = 2 ,   openswmm::EngineState::RUNNING = 3 ,   openswmm::EngineState::PAUSED = 4 ,   openswmm::EngineState::ENDED = 5 ,   openswmm::EngineState::REPORTED = 6 ,   openswmm::EngineState::CLOSED = 7 ,   openswmm::EngineState::ERROR_STATE = 8 ,   openswmm::EngineState::BUILDING = 9 }
	High-level engine lifecycle state. More...
enum class	openswmm::UserFlagType : int {   openswmm::UserFlagType::BOOLEAN = 0 ,   openswmm::UserFlagType::INTEGER = 1 ,   openswmm::UserFlagType::REAL = 2 ,   openswmm::UserFlagType::STRING = 3 }
	Value type for a user flag. More...

Detailed Description

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Copyright

Copyright (c) 2026 HydroCouple. All rights reserved.

License\n MIT License

Typedef Documentation

UserFlagValue

using openswmm::UserFlagValue = typedef std::variant<bool, int, double, std::string>

A concrete flag value assigned to a specific object.

Enumeration Type Documentation

EngineState

enum class openswmm::EngineState : int32_t

strong

High-level engine lifecycle state.

Mirrors SWMM_EngineState in include/openswmm/engine/openswmm_engine.h but lives in the C++ domain (scoped enum).

Enumerator
CREATED	Context allocated, no input loaded.
OPENED	Input file parsed, objects allocated.
INITIALIZED	Initial conditions applied.
RUNNING	Simulation loop in progress.
PAUSED	Simulation paused (future hot-swap support)
ENDED	Simulation loop completed.
REPORTED	Summary report written.
CLOSED	Resources released.
ERROR_STATE	Fatal error; call swmm_engine_last_error()
BUILDING	Programmatic model construction in progress (no .inp)

UserFlagType

enum class openswmm::UserFlagType : int

strong

Value type for a user flag.

Enumerator
BOOLEAN	YES/NO/TRUE/FALSE/1/0.
INTEGER	Signed integer.
REAL	Double-precision floating-point.
STRING	Arbitrary string.