Re: [CMake] Link against exe on Windows fails - .a file not found
Looks like I can use ar to generate the .a file for me, regardless of generator
- plugins seem to link and load just fine when doing this. Awesome! :)
if(WIN32)
#Invoke ar to generate a .dll.a from the .obj files, required to link
plugins
add_custom_command(TARGET ${PROJECT_NAME} PRE_LINK
COMMAND sh -c "${CMAKE_AR} cr lib${PROJECT_NAME}.dll.a $$(find . -name
'*.obj' -printf '%p ')"
COMMENT "Generating lib${PROJECT_NAME}.dll.a for external linking"
)
#Also add the install command for libws2editor.dll.a
install(FILES ${CMAKE_CURRENT_BINARY_DIR}/lib${PROJECT_NAME}.dll.a
DESTINATION bin)
endif(WIN32)
-Mike
____________
From: Michael Ho <craftedc...@outlook.com>
Sent: 18 May 2018 11:55
To: Jano Svitok; Michael Ho
Cc: cmake@cmake.org
Subject: Re: [CMake] Link against exe on Windows fails - .a file not found
Ah yes, I forgot Windows doesn't export symbols by default.
Unfortunately adding set_target_properties(${PROJECT_NAME} PROPERTIES
WINDOWS_EXPORT_ALL_SYMBOLS 1) didn't seem to help however - I get the same file
not found error.
Something interesting I noticed however is that if I copy and rename
ws2editor/CMakeFiles/ws2editor.dir/objects.a to ws2editor/libws2editor.dll.a,
the plugin links just fine and even works when I run the application. I suppose
I could add this as some post build step, but it certainly feels like a bit of
a hacky solution. This only seems to work for the Unix Makefiles generate
however (Which should be fine, although I had been using ninja at the moment so
certainly not ideal).
Thanks
- Mike
(Note: sorry for the mostly duplicate message - I wasn't aware that you should
use "Reply All" in mailing lists)
From: Jano Svitok <jan.svi...@gmail.com>
Sent: 14 May 2018 00:34
To: Michael Ho
Cc: cmake@cmake.org
Subject: Re: [CMake] Link against exe on Windows fails - .a file not found
On Sun, May 13, 2018 at 1:41 PM, Michael Ho
<craftedc...@outlook.com<mailto:craftedc...@outlook.com>> wrote:
>
> Hey there.
>
> I'm trying to make a plugin system for my application, and thus each plugin
> will need to link with my main application. This is fine on Linux and macOS,
> as I can just set the ENABLE_EXPORTS property of my executable target
> (set_target_properties(${PROJECT_NAME} PROPERTIES ENABLE_EXPORTS 1), and
> plugins will link just fine. On Windows however, clang++ yells at me that it
> can't find libws2editor.dll.a.
>
> clang++.exe: error: no such file or directory: 'ws2editor/libws2editor.dll.a'
>
> Upon looking over the CMake docs, it says "For DLL platforms an import
> library will be created for the exported symbols and then used for linking."
> - This import library file (presumably the .dll.a) never seems to be created
> though.
>
>
> After a bit more digging around I came across
> https://github.com/Kitware/CMake/blob/master/Tests/Plugin/CMakeLists.txt -
> When I clone the CMake repo and try and compile that test myself, it also
> fails with the same error when using clang + ninja! When building with
> MSVC/msbuild however it compiles just fine (My project fails to configure
> when generating files for MSVC however, and ideally I'd like to use the same
> build config across Win/Mac/Linux).
>
> So how can I get the CMake build on Windows to create this file, or otherwise
> link with an executable?
You need to 1. mark some/all symbols to export 2. actually export them
ENABLE_EXPORTS does #2. For #1, you need to either mark each symbol to export
as __declspec(dllexport) or mark all symbols with WINDOWS_EXPORT_ALL_SYMBOLS
(see
https://blog.kitware.com/create-dlls-on-windows-without-declspec-using-new-cmake-export-all-feature/,
check also comments for possible drawbacks).
https://github.com/Kitware/CMake/blob/master/Tests/Plugin/include/example.h
shows how to use __declspec(dllexport): for each dll you define a macro
(EXAMPLE_EXPORT here) that becomes either export (when #included from dll) or
import (when #included from code linked to dll). Every class/function/variable
you want to use from the plugin must be marked this way (example_exe_function).
For class members, it's enough to mark the class.
Finally there's a #define (example_exe_EXPORTS here) that controls how is the
macro defined. See
https://cmake.org/cmake/help/git-master/prop_tgt/DEFINE_SYMBOL.html (I didn't
know this until now, we used to manually define the symbol!)
Jano
--
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Please keep messages on-topic and check the CMake FAQ at:
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Kitware offers various services to support the CMake community. For more
information on each offering, please visit:
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CMake Consulting: http://cmake.org/cmake/help/consulting.ht
Re: [CMake] Link against exe on Windows fails - .a file not found
Ah yes, I forgot Windows doesn't export symbols by default.
Unfortunately adding set_target_properties(${PROJECT_NAME} PROPERTIES
WINDOWS_EXPORT_ALL_SYMBOLS 1) didn't seem to help however - I get the same file
not found error.
Something interesting I noticed however is that if I copy and rename
ws2editor/CMakeFiles/ws2editor.dir/objects.a to ws2editor/libws2editor.dll.a,
the plugin links just fine and even works when I run the application. I suppose
I could add this as some post build step, but it certainly feels like a bit of
a hacky solution. This only seems to work for the Unix Makefiles generate
however (Which should be fine, although I had been using ninja at the moment so
certainly not ideal).
Thanks
- Mike
(Note: sorry for the mostly duplicate message - I wasn't aware that you should
use "Reply All" in mailing lists)
From: Jano Svitok <jan.svi...@gmail.com>
Sent: 14 May 2018 00:34
To: Michael Ho
Cc: cmake@cmake.org
Subject: Re: [CMake] Link against exe on Windows fails - .a file not found
On Sun, May 13, 2018 at 1:41 PM, Michael Ho
<craftedc...@outlook.com<mailto:craftedc...@outlook.com>> wrote:
>
> Hey there.
>
> I'm trying to make a plugin system for my application, and thus each plugin
> will need to link with my main application. This is fine on Linux and macOS,
> as I can just set the ENABLE_EXPORTS property of my executable target
> (set_target_properties(${PROJECT_NAME} PROPERTIES ENABLE_EXPORTS 1), and
> plugins will link just fine. On Windows however, clang++ yells at me that it
> can't find libws2editor.dll.a.
>
> clang++.exe: error: no such file or directory: 'ws2editor/libws2editor.dll.a'
>
> Upon looking over the CMake docs, it says "For DLL platforms an import
> library will be created for the exported symbols and then used for linking."
> - This import library file (presumably the .dll.a) never seems to be created
> though.
>
>
> After a bit more digging around I came across
> https://github.com/Kitware/CMake/blob/master/Tests/Plugin/CMakeLists.txt -
> When I clone the CMake repo and try and compile that test myself, it also
> fails with the same error when using clang + ninja! When building with
> MSVC/msbuild however it compiles just fine (My project fails to configure
> when generating files for MSVC however, and ideally I'd like to use the same
> build config across Win/Mac/Linux).
>
> So how can I get the CMake build on Windows to create this file, or otherwise
> link with an executable?
You need to 1. mark some/all symbols to export 2. actually export them
ENABLE_EXPORTS does #2. For #1, you need to either mark each symbol to export
as __declspec(dllexport) or mark all symbols with WINDOWS_EXPORT_ALL_SYMBOLS
(see
https://blog.kitware.com/create-dlls-on-windows-without-declspec-using-new-cmake-export-all-feature/,
check also comments for possible drawbacks).
https://github.com/Kitware/CMake/blob/master/Tests/Plugin/include/example.h
shows how to use __declspec(dllexport): for each dll you define a macro
(EXAMPLE_EXPORT here) that becomes either export (when #included from dll) or
import (when #included from code linked to dll). Every class/function/variable
you want to use from the plugin must be marked this way (example_exe_function).
For class members, it's enough to mark the class.
Finally there's a #define (example_exe_EXPORTS here) that controls how is the
macro defined. See
https://cmake.org/cmake/help/git-master/prop_tgt/DEFINE_SYMBOL.html (I didn't
know this until now, we used to manually define the symbol!)
Jano
--
Powered by www.kitware.com
Please keep messages on-topic and check the CMake FAQ at:
http://www.cmake.org/Wiki/CMake_FAQ
Kitware offers various services to support the CMake community. For more
information on each offering, please visit:
CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html
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[CMake] Link against exe on Windows fails - .a file not found
Hey there.
I'm trying to make a plugin system for my application, and thus each plugin
will need to link with my main application. This is fine on Linux and macOS, as
I can just set the ENABLE_EXPORTS property of my executable target
(set_target_properties(${PROJECT_NAME} PROPERTIES ENABLE_EXPORTS 1), and
plugins will link just fine. On Windows however, clang++ yells at me that it
can't find libws2editor.dll.a.
clang++.exe: error: no such file or directory: 'ws2editor/libws2editor.dll.a'
Upon looking over the CMake docs, it says "For DLL platforms an import library
will be created for the exported symbols and then used for linking." - This
import library file (presumably the .dll.a) never seems to be created though.
After a bit more digging around I came across
https://github.com/Kitware/CMake/blob/master/Tests/Plugin/CMakeLists.txt - When
I clone the CMake repo and try and compile that test myself, it also fails with
the same error when using clang + ninja! When building with MSVC/msbuild
however it compiles just fine (My project fails to configure when generating
files for MSVC however, and ideally I'd like to use the same build config
across Win/Mac/Linux).
So how can I get the CMake build on Windows to create this file, or otherwise
link with an executable?
Thanks.
If you want the full CMake scripts, they're available on GitHub.
The main executable:
https://github.com/CraftedCart/smblevelworkshop2/blob/e85c2a0f6f9eb9a00f22b94aa79426b0874ca8e1/ws2editor/CMakeLists.txt
The plugin:
https://github.com/CraftedCart/smblevelworkshop2/blob/e85c2a0f6f9eb9a00f22b94aa79426b0874ca8e1/ws2editorplugins/ws2editorexampleplugin/CMakeLists.txt
--
Powered by www.kitware.com
Please keep messages on-topic and check the CMake FAQ at:
http://www.cmake.org/Wiki/CMake_FAQ
Kitware offers various services to support the CMake community. For more
information on each offering, please visit:
CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html
Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html
Follow this link to subscribe/unsubscribe:
https://cmake.org/mailman/listinfo/cmake
