# Predefined symbols The following symbols are predefined in the IDC preprocessor: ``` _NT_ IDA is running under MS Windows _LINUX_ IDA is running under Linux _MAC_ IDA is running under Mac OS X _UNIX_ IDA is running under Unix (linux or mac) _EA64_ 64-bit version IDA _QT_ GUI version of IDA (Qt) _GUI GUI version of IDA _TXT_ Text version of IDA _IDA_VERSION_ The current IDA version. For example: "9.0" _IDAVER_ The current, numerical IDA version. For example: "900" means v9.0 ``` These symbols are also defined when parsing C header files. --- # Agent Instructions: 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: ``` GET https://docs.hex-rays.com/9.0sp1/developer-guide/idc/core-concepts/predefined-symbols.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.