# Cannot include header files inside the header files in library project (With executable project for testing)

**URL:** https://discourse.cmake.org/t/cannot-include-header-files-inside-the-header-files-in-library-project-with-executable-project-for-testing/15311
**Category:** Code
**Tags:** os:linux, comp:gcc, comp:clang, gen:ninja
**Created:** [November 16, 2025, 12:17pm UTC](https://discourse.cmake.org/t/cannot-include-header-files-inside-the-header-files-in-library-project-with-executable-project-for-testing/15311 "2025-11-16T12:17:12Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![ClausKlein](https://discourse.cmake.org/user_avatar/discourse.cmake.org/clausklein/32/352_2.png) [@ClausKlein](https://discourse.cmake.org/u/ClausKlein)
#### Post date: [November 16, 2025, 1:52pm UTC](https://discourse.cmake.org/t/cannot-include-header-files-inside-the-header-files-in-library-project-with-executable-project-for-testing/15311/3 "2025-11-16T13:52:47Z")

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I would use FILE\_SET HEADERS with BASE\_DIRS include.

See [I can't understand an error about INTERFACE\_SOURCES and prefix - #9 by ben.boeckel](https://discourse.cmake.org/t/i-cant-understand-an-error-about-interface-sources-and-prefix/10105/9)

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