How do I compile+link my code without using cmake?

[TassieBruce]

It would appear that the only documentation regarding compiling and linking my code with matplot++ assumes the use of cmake. Can anyone tell me how to this for a project that does not use cmake?

It would be nice if there was a matplot++.pc file installed since enabling pkg-config would simplify things for non-cmake usage.

ETA: I'm using linux - debian 11 with matplot++ installed to /usr/local
ETA2: I use meson to build but a list of cflags and ldflags would suffice.

[alandefreitas]

If you want to compile it with another build system, then you'd have to replicate everything starting from https://github.com/alandefreitas/matplotplusplus/blob/master/CMakeLists.txt

If you just want to link a version you have installed, then you'd have to replicate the contents of the final matplot++-config.cmake file (generated from this) that's going to be in your installation directory. This matplot++-config.cmake is the cmake equivalent of a package config matplot++.pc.

I don't think there's a way an simple way to generate a matplot++.pc from the current build scripts. Maybe there could be a small template with the flags you need. But there are still lots of dependencies to link and matplot++.pc would probably get behind matplot++-config.cmake all the time.

[TassieBruce]

Thanks for that. I presume the important details are in
INTERFACE_INCLUDE_DIRECTORIES and INTERFACE_LINK_LIBRARIES found in
/usr/local/lib/cmake/Matplot++Targets.cmake

Is there a good reason why the following does not produce useable output?

$ cmake --find-package -DNAME=Matplot++ -DCOMPILER_ID=GNU -DLANGUAGE=CXX -DMODE=COMPILE

I get the output:

CMake Warning at /usr/local/lib/cmake/Matplot++/Matplot++Config.cmake:34 (message):
  This installation of Matplot++ was built with GNU.
Call Stack (most recent call first):
  /usr/share/cmake-3.18/Modules/CMakeFindPackageMode.cmake:183 (find_package)


CMake Error at /usr/share/cmake-3.18/Modules/CheckIncludeFileCXX.cmake:92 (try_compile):
  The TRY_COMPILE() command is not supported in --find-package mode.
Call Stack (most recent call first):
  /usr/local/lib/cmake/Matplot++/FindFilesystem.cmake:157 (check_include_file_cxx)
  /usr/share/cmake-3.18/Modules/CMakeFindDependencyMacro.cmake:47 (find_package)
  /usr/local/lib/cmake/Matplot++/Matplot++Config.cmake:42 (find_dependency)
  /usr/share/cmake-3.18/Modules/CMakeFindPackageMode.cmake:183 (find_package)


Matplot++ not found.
CMake Error: Problem processing arguments. Aborting.

I suspect if this worked, meson would be able to find the dependency.

[alandefreitas]

If I'm not wrong, I think cmake --find-package is deprecated. In any case, it seems like it looks for matplot++ without setting a toolchain and Matplot++Config.cmake returns an error saying it was built with a different "compiler". Maybe removing this message "This installation of Matplot++ was built ..." from Matplot++Config.cmake could give you what you want, but I'm really not sure.

[TassieBruce]

Yeah, I don't know what that warning is about. I already tried building with clang and g++ and that warning and the later error are there in both cases. Anyway, that is just a warning, the error comes later. But cmake --find-package does work for other installed packages on my system like -DNAME=Boost and -DNAME=PulseAudio

Anyway, thanks for your help with this. I have found a solution that works for me using meson build. I'll post it as a reply to my original question outside this thread.

[alandefreitas]

Yeah, I don't know what that warning is about

The warning is telling you are using compiler A but your matplot++ installation was built with compiler B. However, the config script is just wrong on this one. What's happening (probably) is --find-package simply sets no compiler toolchain. So it just compares "" to "GNU" and this condition returns false.

It's really an edge case. To avoid this in future versions, you could open a PR changing the matplot++-config.cmake template to only consider this condition when both strings are not empty.

[TassieBruce]

Answering myself with a solution that works when using the meson build system.

meson can use cmake's find_package() function to find dependencies. I had tried using the dependency in my meson.build file:

matplotdep = dependency('Matplot++')

which failed but I stupidly didn't read the error message fully. Matplot++ produces several modules which must be given as an argument to dependency(). The following snippet in my meson.build file will build the example matplotplusplus/examples/line_plot/plot/plot_3.cpp

matplotdep = dependency('Matplot++', 
                        modules: ['Matplot++::nodesoup', 
                                  'Matplot++::cimg', 
                                  'Matplot++::matplot'])
executable('plot_3', sources: ['plot_3.cpp'],
           dependencies: [matplotdep])

There is one more possible module 'std::filesystem' that isn't necessary for plot_3.cpp

[alandefreitas]

That's interesting. That's probably not what integration would look like if the original build system were meson. "Matplot++" should already link all of that stuff. But this looks good enough for something that's been inferred. Great!