Product: RBC_GA, the Generic Application of the reference RBC (repository RBC_GA). Layer: Generic Application, above RBC_GP. Language: C99. Output: librte_rbc2oo2_ga.{dylib,so} (rbc2oo2::ga). Assessment unit: Generic Application (assessed per application class), see ../../docs/safety/CERTIFICATION_PLAN.dox.

Responsibility

The signalling adaptation logic that turns interlocking and CTC events into decisions for RBC_GP:

IL adapter: tracks route add and release from the interlocking; on GP's route connect and disconnect it grants or shrinks the Movement Authority.
CTC adapter: builds the CTC indications (train connected, MA granted, MA extended, and the on-change CTC_TRAIN_INFO telemetry).
MA logic adaptation: the single entry point GP calls; registers GA's callbacks with GP.
Site projection: a route-only view of site data (ab_siteGA.h), implemented by RBC_SA.

It does not own train sessions, the route and train database, ERTMS procedures, cross-comparison or communication. Those belong to RBC_GP. It never decides which train a route belongs to; GP's position-based connect gate does.

Everything marked project-specific (the site projection and any project rules) is replaced per project.

Interfaces exposed to other products

Interface	Form	Consumed by	Notes
Init entry point ab_ga_ma_adaptation_init()	C function, declared in RBC_GP's ga_interface.h	RBC_GP	The only bare call from GP into GA
Shared library librte_rbc2oo2_ga	rbc2oo2::ga, installed by RBC_GP into dist/<platform>/lib/	RBC_GP at run time	Must sit next to the real librte_gp
Site contract include/ab_siteGA.h	Reduced route table (id, start_signal, end_signal, length_m)	RBC_SA implements it as sa::site::ga	Hand-kept in sync with GP's full topology

Interfaces required

Needs	From	How
ga_interface.h, common/ (wire types, site config)	RBC_GP	Header-only reach into GP's source tree (RTE_RBC2OO2GP_DIR)
sa::site::ga	RBC_SA	Static library, RTE_RBC2OO2SA_DIR or installed package
Status, buffer, logging, app manager	Platform_RTE	rte::* targets

Build and test

cmake -S . -B build # standalone: just the shared library

cmake --build build && ctest --test-dir build --output-on-failure

Where to read next

Working notes, rules and gotchas: CLAUDE.md
Design history: docs/DESIGN_NOTES.dox
MISRA screening pass (cppcheck, no licensed rule text): docs/MISRA_COMPLIANCE_REPORT.dox
Workspace context: ../../docs/architecture/OVERVIEW.dox

In practice GA is built as part of RBC_GP, which adds it as a subdirectory and also produces the role C IL and CTC gateway binaries. Rules and details: CLAUDE.md; design history: docs/DESIGN_NOTES.dox.