Trace Terminologies

This topic lists the various trace terminologies that are changed or added in UTF 2.0.

ModuleUid

The secondary filter in UTF 1.0 is replaced with ModuleUid in UTF 2.0.

Every trace packet is assigned a default value 0 to ModuleUid by its originating trace point to indicate the code module in which the trace point is defined. You are recommended to override the default value ModuleUid by adding the macro MACRO - EXECUTABLE_DEFAULT_MODULEUID=0xuid3 to your MMP file.

A common value for the ModuleUid is the UID3 of the associated binary file. In some cases, it is not suitable to use the UID3 as a ModuleUid. For example, you may not need to trace across the entire component, if it is very big. In such cases, you can obtain a unique ModuleUid from SymbianSigned and assign to a particular use case or set a ModuleUid for each instance of TTraceContext without setting a default value for the component.

For details about SymbianSigned, see https://www.symbiansigned.com.

Note: A ModuleUid must not be used for trace points in more than one compiled binary file.

Classification

The primary filter in UTF 1.0 is replaced with Classification in UTF 2.0.

Every trace packet is assigned a classification by its originating trace point. This is a label that indicates the intended use of the trace points or trace packets.

The classification can reflect a system-wide tracing use-case, such as indicating why a Panic occurred. It can also be assigned to trace packets from performance critical software, such as the kernel or other key services.

Note: The ModuleUid and Classification attributes of a trace point are independent.

FormatId

The 1-byte schema in UTF 1.0 is replaced with 2-byte FormatId.

FormatId is a numerical value assigned to a trace point which is used on the host PC to look up the format of the associated trace packets.

The meaning of a FormatId is specific to the ModuleUid of the associated trace packet. For example, the FormatId 1 can be interpreted on the host PC as “RProcess::Create returned %d ” for the ModuleUid 130e0751 but can be interpreted as “Something - odd happened: %s ” for the ModuleUid 1000015c.

Note: A trace point with no FormatId (using a Printf call instead of a Trace call) indicates that the trace packet contains text and needs no further formatting.

Trace Point Context

The trace point context is newly added in UTF 2.0. It includes information describing the circumstances of a trace point. The trace point context data is used to include certain data in the trace packet generated at run-time.

The context of a trace point can include information such as source code line, source file and binary file. It can be used to map trace information to the source.

Note: A trace point context can be re-used by several trace points.

UTF Namespace

The UTF namespace is newly added in UTF 2.0. It contains a set of libraries providing the trace point, trace filter, storage, buffer management and transport APIs required on the device for tracing to be performed.