# CMAKE\_WINDOWS\_EXPORT\_ALL\_SYMBOLS exports "=="

**URL:** https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314
**Category:** Usage
**Tags:** os:windows, comp:msvc
**Created:** [June 12, 2023, 8:39am UTC](https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314 "2023-06-12T08:39:42Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Ohjurot](https://discourse.cmake.org/user_avatar/discourse.cmake.org/ohjurot/32/3523_2.png) [@Ohjurot](https://discourse.cmake.org/u/Ohjurot)
#### Post date: [June 12, 2023, 8:39am UTC](https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314/1 "2023-06-12T08:39:42Z")

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Hello,

I’m currently migrating an Open Source lib into a package manager using CMake.  
During my testing, I found that CMake exports “==” to “exports.def” when using CMAKE\_WINDOWS\_EXPORT\_ALL\_SYMBOLS (Required in the current state of the lib). This only happens during debug builds.

Does anybody have any advice on how to prevent that, or is this a bug and I should file an issue on GitLab?

Thanks in Advance!

Edit:  
Compiler Output:

```auto
exports.def : error LNK2001: Nicht aufgelöstes externes Symbol "=". [C:\Users\z003x0uk\.conan2\p\b\nanafcdbcb5d6582f\b\build\nana.vcxproj]
C:/Users/z003x0uk/.conan2/p/b/nanafcdbcb5d6582f/b/build/Debug/nana.lib : fatal error LNK1120: 1 nicht aufgelöste Externe [C:\Users\z003x0uk\.conan2\p\b\nanafcdbcb5d6582f\b\build\nana.vcxproj]

```

exports.def (relevant part):

```auto
	?wave_native_if@detail@audio@nana@@3Vwave_native@123@A DATA
	==
	??$?0$$BY0BAE@_W$0A@@path@filesystem@std@@QEAA@AEAY0BAE@$$CB_WW4format@012@@Z

```

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<div class="post-metadata">

### Author: ![craig.scott](https://discourse.cmake.org/user_avatar/discourse.cmake.org/craig.scott/32/20_2.png) [@craig.scott](https://discourse.cmake.org/u/craig.scott)
#### Post date: [June 12, 2023, 9:52pm UTC](https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314/2 "2023-06-12T21:52:46Z")

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If you can put together a minimal, complete example project that reproduces the bug, I suggest [opening an issue](https://gitlab.kitware.com/cmake/cmake/-/issues/new) in the issue tracker. It also appears that you are using a non-English locale. If you’re able, it may be worth checking whether you still see the problem if using an English locale like `en_US.UTF-8` (I doubt it will make a difference, but worth checking).

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<div class="post-metadata">

### Author: ![Ohjurot](https://discourse.cmake.org/user_avatar/discourse.cmake.org/ohjurot/32/3523_2.png) [@Ohjurot](https://discourse.cmake.org/u/Ohjurot)
#### Post date: [June 14, 2023, 7:40am UTC](https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314/3 "2023-06-14T07:40:19Z")

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Thank you for your response. I will open an issue today. Sadly it requires a bit of setup and dependencies, since I was not able to reproduce the bug without the lib to be compiled.

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<div class="post-metadata">

### Author: ![ben.boeckel](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [June 17, 2023, 8:58pm UTC](https://discourse.cmake.org/t/cmake-windows-export-all-symbols-exports/8314/4 "2023-06-17T20:58:06Z")

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I would recommend finding the source/object file that causes this symbol to be exported and narrow things down that way. Basically just comment out half of the sources and bisect it down to at least one example source causing it.