> 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/core/types/concepts/assembler-level-and-c-level-types.md). # Assembler & C Level Types Details In order to provide intuitive yet powerful interface to types IDA introduces two kinds of types: * Assembler level types * C level types Assembler level types are the ones defined by the user using the [Local Types](/core/user-interface/concepts/subviews.md#local-types-window) view. Since the user has to specify manually the member offset and other attributes, IDA considers the member offsets to be fixed for them and never shifts members of such types. If a member of struct becomes too big and does not fit the struct anymore, IDA will delete it. The types defined in the [Local types](/core/user-interface/concepts/subviews.md#local-types-window) window are considered as C level types. For them IDA automatically calculates the member offsets and if necessary may shift members and change the total struct size. The user may change the type level by simply editing the type from the appropriate window. In the Local Types view: * C level types are displayed using regular colors. * Assembler level types are displayed in gray, as if they are disabled (but they are not). --- # 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 by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.hex-rays.com/core/types/concepts/assembler-level-and-c-level-types.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.