> For the complete documentation index, see [llms.txt](https://docs.hex-rays.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hex-rays.com/ida-9.5/ida-actions/loadheaderfile.md).

# LoadHeaderFile

## Description

This command allows you to apply type declarations from a C header file to the program. IDA reads and parses the specified header file with its clang-based parser, the same way a compiler front-end does. C, C++, Objective-C and Objective-C++ headers are supported out of the box. Note:

* Only type declarations are collected. The function definitions in the input file are skipped.

Don't forget to specify the compiler and memory model in the compiler setup dialog box (Options → Compiler...) before loading a header file. All type declarations found in the input file are stored in the current database in the form of a type library. These type declarations can be used to define new structure and enumeration definitions.

In the case of an error in the input file, the error messages appear in the message window. In any case, the type declarations that are already parsed are not deleted from the database.


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# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.hex-rays.com/ida-9.5/ida-actions/loadheaderfile.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.