1# HiTraceId 2 3 4## Overview 5 6Defines a **HiTraceId** instance. 7 8**System capability**: SystemCapability.HiviewDFX.HiTrace 9 10**Since**: 12 11 12**Related module**: [Hitrace](_hitrace.md) 13 14**Header file**: [trace.h](trace_8h.md) 15 16## Summary 17 18 19### Member Variables 20 21A little-endian **HiTraceId** consists of the following fields in sequence: 22 23| Field| Number of Bits| Description| 24| -------- | -------- | -------- | 25| uint64_t [valid](_hitrace.md#valid) | 1 | Whether **HiTraceId** is valid. | 26| uint64_t [ver](_hitrace.md#ver) | 3 | Version number of **HiTraceId**. | 27| uint64_t [chainId](_hitrace.md#chainid) | 60 | Chain ID of **HiTraceId**. | 28| uint64_t [flags](_hitrace.md#flags) | 12 | Flag of **HiTraceId**. | 29| uint64_t [spanId](_hitrace.md#spanid) | 26 | Span ID of **HiTraceId**. | 30| uint64_t [parentSpanId](_hitrace.md#parentspanid) | 26 | Parent span ID of **HiTraceId**. | 31 32A big-endian **HiTraceId** consists of the following fields in sequence: 33 34| Field| Number of Bits| Description| 35| -------- | -------- | -------- | 36| uint64_t [chainId](_hitrace.md#chainid) | 60 | Chain ID of **HiTraceId**. | 37| uint64_t [ver](_hitrace.md#ver) | 3 | Version number of **HiTraceId**. | 38| uint64_t [valid](_hitrace.md#valid) | 1 | Whether **HiTraceId** is valid. | 39| uint64_t [parentSpanId](_hitrace.md#parentspanid) | 26 | Parent span ID of **HiTraceId**. | 40| uint64_t [spanId](_hitrace.md#spanid) | 26 | Span ID of **HiTraceId**. | 41| uint64_t [flags](_hitrace.md#flags) | 12 | Flag of **HiTraceId**. | 42