add nativeapis

Signed-off-by: Nzengyawen <zengyawen1@huawei.com>

en/application-dev/reference/native-apis/_raw_file_descriptor.md

+# RawFileDescriptor
+
+
+## Overview
+
+Provides rawfile descriptor information.
+
+**RawFileDescriptor** is an output parameter of [OH_ResourceManager_GetRawFileDescriptor](rawfile.md#oh_resourcemanager_getrawfiledescriptor). It provides information including the rawfile descriptor and the start position and length of the rawfile in the HAP package.
+
+**Since:**
+8
+
+**Related Modules:**
+
+[Rawfile](rawfile.md)
+
+
+## Summary
+
+
+### Member Variables
+
+| Name | Description | 
+| -------- | -------- |
+| [fd](#fd) |rawfile descriptor  | 
+| [start](#start) | Start position of rawfile in the HAP package  | 
+| [length](#length) | Length of rawfile in the HAP package  | 
+
+
+## Member Variable Description 
+
+
+### fd
+
+  
+```
+int RawFileDescriptor::fd
+```
+**Description**<br>
+rawfile descriptor
+
+
+### length
+
+  
+```
+long RawFileDescriptor::length
+```
+**Description**<br>
+Length of rawfile in the HAP package
+
+
+### start
+
+  
+```
+long RawFileDescriptor::start
+```
+**Description**<br>
+Start position of rawfile in the HAP package