1e41f4b71Sopenharmony_ci# MediaLibrary_RequestId
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4e41f4b71Sopenharmony_ci## Overview
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6e41f4b71Sopenharmony_ciDefines a request ID, which is a universally unique identifier (UUID) of a request.
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8e41f4b71Sopenharmony_ciA value of this type is returned when a media asset is requested. The request ID can be used to cancel a request. 
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10e41f4b71Sopenharmony_ciIf a request fails, an all-zero value, for example, **00000000-0000-0000-0000-000000000000** is returned.
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12e41f4b71Sopenharmony_ci**Since**: 12
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14e41f4b71Sopenharmony_ci**Related module**: [MediaAssetManager](_media_asset_manager.md)
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17e41f4b71Sopenharmony_ci## Summary
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20e41f4b71Sopenharmony_ci### Member Variables
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22e41f4b71Sopenharmony_ci| Name| Description |
23e41f4b71Sopenharmony_ci| -------- | -------- |
24e41f4b71Sopenharmony_ci| char [requestId](#requestid) [UUID_STR_MAX_LENGTH] | Maximum length of a request ID. |
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27e41f4b71Sopenharmony_ci## Member Variable Description
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30e41f4b71Sopenharmony_ci### requestId
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32e41f4b71Sopenharmony_ci```
33e41f4b71Sopenharmony_cichar MediaLibrary_RequestId::requestId[UUID_STR_MAX_LENGTH]
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35e41f4b71Sopenharmony_ci**Description**
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37e41f4b71Sopenharmony_ciSpecifies the maximum length of a request ID.