namespace apext::log

With the function template TraceArti, the namespace apext::log provides an interface for forwarding modeled trace messages to external runtime trace tools [SWS_LOG_20000]. The function is invoked exclusively internally by the logger framework when switching between logging and tracing, and processes message-specific identifiers as well as variable parameters [SWS_LOG_20000]. Key constraints include minimal runtime overhead, complete thread safety, and exception-safe execution without error or return values.

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Context

The namespace apext::log provides functional interfaces for the logging and tracing subsystem of the AUTOSAR Adaptive Platform. Its primary responsibility lies in providing a dedicated interface for external runtime trace tools via the function template TraceArti [SWS_LOG_20000]. As an interpretation, the naming with prefix apext is likely to indicate that it is a platform extension (Adaptive Platform Extension) that connects specific tracing mechanisms such as the AUTOSAR Run-Time Interface (ARTI) to the logging framework. Question Q-325896ce9f6b8e42 (open)

In the system architecture, the namespace acts as a link between the internal logging infrastructure and downstream analysis or trace tools. Essentially three components interact with one another: the internal logger framework, the interface function TraceArti within apext::log, and the attached trace tool [SWS_LOG_20000]. The logger framework processes application events and forwards modeled messages upon appropriate switching to TraceArti, which passes the data to the vendor-specific trace tool [SWS_LOG_20000].

Context diagram: Embedding of TraceArti between logger framework and trace tool. Sources: [SWS_LOG_20000]

Lifecycle

The namespace apext::log does not encapsulate any long-lived class instances, session objects, or stateful entities with an independent lifecycle. No explicit initialization or termination routines exist in the namespace; rather, the functionality is implemented exclusively through free template functions [SWS_LOG_20000]. The lifecycle of the tracing functionality is thus entirely coupled to the overall operational lifecycle of the logger framework.

Strict guarantees apply regarding concurrency behavior and operational safety: The interface TraceArti is explicitly specified as thread-safe [SWS_LOG_20000]. This allows the logger framework to delegate trace invocations in parallel from multiple execution contexts and threads to the namespace without external synchronization. At the same time, the function is declared as exception safe and noexcept [SWS_LOG_20000], so that no resource leaks or uncontrolled stack unwinding states can occur during the call at any time.

Usage Path

The functions of namespace apext::log are not designed for direct invocation by general application software. Instead, TraceArti is called exclusively internally by the logger framework when switching between classic logging and ARTI-based tracing [SWS_LOG_20000]. Developers or integrators include the appropriate header file #include "apext/log/trace_arti.h" as needed to obtain access to the declaration [SWS_LOG_20000].

Upon invocation, the function processes modeled messages that are specific to the trace tool in use [SWS_LOG_20000]. For this purpose, the interface accepts a message-identifying identifier msg_id of an implementation-defined type MsgId as well as a variable parameter pack params... of arbitrary types Params... [SWS_LOG_20000]. To keep runtime costs in the trace path as low as possible, the specification requires strict minimization of runtime overhead; this is to be achieved, for example, through tailored template specializations based on the respective MsgId [SWS_LOG_20000]. It is to be assumed that such specializations are typically generated by tool generators as part of toolchain integration for the respective target systems.

Error Scenarios

In terms of error handling, apext::log pursues a fault-tolerant design without signaling runtime errors to the caller. The function signature of TraceArti defines no return value (void) and completely prohibits throwing C++ exceptions via the noexcept specification [SWS_LOG_20000]. Preconditions such as the validity of message IDs and passed payload data must therefore be ensured by the calling logger framework or the corresponding specializations, as no error codes can be transported in the event of an error [SWS_LOG_20000].