<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le sam. 25 mai 2019 à  13:51, Bill Somerville <<a href="mailto:bill@classdesign.com" target="_blank">bill@classdesign.com</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">Hi Robert,</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix"><br>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">thanks for that, the target name change
does seem to help but I am still unable to achieve my goal. Here
is a simplified example that demonstrates the problem:</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">
<pre>cmake_minimum_required (VERSIONÂ 3.1.0 FATAL_ERROR)
project (demo LANGUAGES NONE)
add_custom_target (prog_target COMMAND ${CMAKE_COMMAND} -E touch prog${CMAKE_EXECUTABLE_SUFFIX})
add_executable (prog IMPORTED)
add_dependencies (prog prog_target)
set_target_properties (prog PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_BINARY_DIR}/prog${CMAKE_EXECUTABLE_SUFFIX})
install (TARGETS prog RUNTIME DESTINATION bin)</pre>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">which gives the following error at
CMake configuration:</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">
<pre>CMake Error at CMakeLists.txt:7 (install):
install TARGETS given target "prog" which does not exist.
-- Configuring incomplete, errors occurred!
</pre>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">So the target that 'add_executable(name
IMPORTED)' creates is not a real executable target. I can change
its properties but the 'install(TARGETS ...)' command thinks it
does not exist. Note that a executable target is a very simple
demonstration and I understand that I can use 'install(PROGRAM
...)' just about as easily, but when it comes to a shared library
it gets a lot more complex when using, exporting, and instlling
it, and it seems that IMPORTED targets fall well short of useful
when they are actually produced by the current CMake project.</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix"><br>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">I can understand that an IMPORTED
target is perhaps not meant to be installable</div></div></blockquote><div><br></div><div>Robert will give his advice on that but I bet IMPORTED target were never meant to be drop-in *replacement* of genuine target.</div><div><br></div><div>They were meant to ease *reference to* object/lib:executable that are outside the build of the project.</div><div>e.g the doc says:Â <a href="https://cmake.org/cmake/help/latest/command/add_library.html#imported-libraries" target="_blank">https://cmake.org/cmake/help/latest/command/add_library.html#imported-libraries</a></div><div>"An IMPORTED library target references a library file located outside the project"</div><div><br></div><div>Nmelly a target that is "already installed somewhere" and that you want to reference in your CMake build.</div><div>Â </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div bgcolor="#FFFFFF"><div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix"> but if so then your
statement that "The goal that you have is fully supported by
CMake" seems to be incorrect. To reiterate, I am trying to use
foreign tools to make binary targets and wish to have CMake treat
them *as if* they were created by supported languages like C, ++,
or Fortran. Am I still missing something?<br></div></div></blockquote><div><br></div><div>My opinion is that IMPORTED target are not designed (as of today) for that purpose.</div><div><br></div><div>When you want to do what you seem to want you need to either:</div><div>1) add a "new LANGUAGE" (you seem to be willing to add golang)</div><div>  see: <a href="https://stackoverflow.com/questions/7978517/how-do-i-get-cmake-to-work-with-the-go-programming-language">https://stackoverflow.com/questions/7978517/how-do-i-get-cmake-to-work-with-the-go-programming-language</a></div><div>  and may be: <a href="https://github.com/aadidenko/golang-cmake-example">https://github.com/aadidenko/golang-cmake-example</a> (or fork of this)</div><div><br></div><div>2) define a set of custom macros that mimic genuine target behaviour.</div><div>  may be see: <a href="https://github.com/cpconduce/go_cmake">https://github.com/cpconduce/go_cmake</a></div><div><br></div><div>If you want to have a look at existing similar example shippped with CMake, have a look at UseJava.cmake module (<a href="https://cmake.org/cmake/help/latest/module/UseJava.html">https://cmake.org/cmake/help/latest/module/UseJava.html</a>)</div><div>You'll see that you have </div><div>add_jar, which is similar to add_executable and create a custom target</div><div>and</div><div>install_jar which is similar to install on genuine target but plays with target properties and install(FILES...) in order to mimic that.<br></div><div>see: <a href="https://github.com/Kitware/CMake/blob/master/Modules/UseJava.cmake">https://github.com/Kitware/CMake/blob/master/Modules/UseJava.cmake</a></div><div><br></div><div>I'm not developing with golang but AFAIK go has a builtin "build system" so bringing go as a language in CMake may not be the best option,</div><div>but again I am no Go expert.</div><div><br></div><div>The only reference of that kind of thing I found in the CMake mailing list is oldish:</div><div><a href="https://cmake.org/pipermail/cmake-developers/2011-August/013715.html">https://cmake.org/pipermail/cmake-developers/2011-August/013715.html</a><br></div><div><br></div><div>May be adding the support for "install" command for IMPORTED target is doable but this seems to be a feature request to be discussed on developer mailing list;</div><div>Regards,</div><div>Eric</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div bgcolor="#FFFFFF"><div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix"><br>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">Regards<br>
Bill Somerville.<br>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix"><br>
</div>
<div class="m_-5720122019321527793gmail-m_-8081222238608490613moz-cite-prefix">On 24/05/2019 20:23, Robert Maynard
wrote:<br>
</div>
<blockquote type="cite">
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">Hi,
The goal that you have is fully supported by CMake. You have just run
into a bug in CMake, and you should report this to
<a class="m_-5720122019321527793gmail-m_-8081222238608490613moz-txt-link-freetext" href="https://gitlab.kitware.com/cmake/cmake/issues" target="_blank">https://gitlab.kitware.com/cmake/cmake/issues</a> .
Basically at a very high level the name out the add_executable target
`callback_generator` is the same as the internal name that CMake is
using for the add_custom_command. This than causes some logic in CMake
(cmTargetTraceDependencies) to incorrectly build another link between
the add_custom_command and your add_executable.
The easiest way to solve this issue is name the add_executable target
to have a different name than the output of your custom command minus
file extension. So maybe something like `callback_generator_exec`
On Fri, May 24, 2019 at 2:02 PM Bill Somerville <a class="m_-5720122019321527793gmail-m_-8081222238608490613moz-txt-link-rfc2396E" href="mailto:bill@classdesign.com" target="_blank"><bill@classdesign.com></a> wrote:
</pre>
<blockquote type="cite">
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">On 13/05/2019 12:03, Bill Somerville wrote:
Hi folks,
I am struggling to understand what the problem is with this:
find_program (GO go)
set (GOPATH "${CMAKE_CURRENT_BINARY_DIR}/go")
file (MAKE_DIRECTORY ${GOPATH})
set (sources ${CMAKE_CURRENT_SOURCE_DIR}/callback_generator.go)
set (build_command ${GO} build)
set (output callback_generator${CMAKE_EXECUTABLE_SUFFIX})
add_custom_command (OUTPUT ${output}
COMMAND ${CMAKE_COMMAND} -E env GOPATH=${GOPATH} CGO_CFLAGS=${CMAKE_CGO_CFLAGS} ${build_command} -o ${output} ${CMAKE_GO_FLAGS} ${sources}
DEPENDS ${sources}
VERBATIM)
add_custom_target (callback_generator_target DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${output})
add_executable (callback_generator IMPORTED)
set_target_properties (callback_generator
PROPERTIES
IMPORTED_LOCATION ${CMAKE_CURRENT_BINARY_DIR}/${output}
)
add_dependencies (callback_generator callback_generator_target)
add_custom_target (server ALL DEPENDS callback_generator)
which gives this error:
</pre>
<blockquote type="cite">
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">cmake --version
</pre>
</blockquote>
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">cmake --version
cmake version 3.14.3
</pre>
<blockquote type="cite">
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">cmake -G "MinGW Makefiles" ..\..
</pre>
</blockquote>
<pre class="m_-5720122019321527793gmail-m_-8081222238608490613moz-quote-pre">cmake -G "MinGW Makefiles" ..\..
-- Configuring done
CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
"callback_generator_target" of type UTILITY
depends on "callback_generator_target" (strong)
The component contains at least one cycle consisting of strong dependencies (created by add_dependencies) that cannot be broken.
The set_target_properties () call seems to be part of the problem but I don't understand why.
Regards
Bill Somerville.
Hi again,
answering my own post since no one has replied. Clearly my question was too specific. Let me try again with a more general question. I have tools that can generate executables (programs, static libraries, and shared libraries, including DLL import libraries on MS Windows). These tools are not directly supported by CMake but they are both needed within a project that uses them and installs them as the project artefacts. How do I integrate, for example a shared library, into a CMake project as if it were produced by a supported toolchain like C or C++? The library is produced by an add_custom_target() command (not add_custom_command() since the underlying tools do their own dependency checking so it is right to run the target commands every build). I need to have a target that I can use in target_link_libraries() and install(TARGETS ...) just like one would with a CMake generated library made with add_library() and programs made with add_executable().
If it helps the tools that are not supported by CMake are the Go language build tools. The project builds some Go programs as utilities but the main project artefact is a shared library with a C language API built using the cgo tools. There are many of C and C++ test programs and example programs as well in the project which need to link against the project shared library etc.
Regards
Bill Somerville.
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="m_-5720122019321527793gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>Eric<br></div></div></div></div></div></div>