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