Allow building the library only, without tools and sound devices support

[Wohlstand]

Currently, both CMake and Autotools builder do always produce builds of both library and executable, and I didn't find any settings to disable build of executable, audio output and all related configure checks. For several purposes (such as making portable applications, games, mobile applications, etc.), it's possible to take a copy of the repository and build the library together with the main application in the same package. In such cases, included demo/helper tools were usually disabled as they are totally unneeded for application use, and there is no reason to build them. There is around the stripped fork of FluidSynth called FluidLite, but it doesn't seem to make any major progress for a while.

EDIT: clarified the paragraph above

And I think, would be cool to allow build scripts to build the:

• library only (don't build executable)
• for some other cases, disable some parts of the library such as the built-in MIDI sequencer or some other, keeping real-time MIDI API only
• disable audio output devices support, keep only raw output PCM/float calls to let developer handle all audio output by theme selves.
• etc.

What do you think?

[derselbst]

Currently, both CMake and Autotools builders do always produce builds of both library and tools, and I didn't find any settings to disable tools and audio output

Fluidsynth doesn't have an "Autotools builder". The one and only build system is CMake. And this already provides various options to compile a hilghly customized, stripped down version of fluidsynth. I don't know, to which "tools" you are referring. By default, fluidsynth's library and the executable are compiled. Demos and unit tests are only compiled when explicitly asked for. Hence, it is not really clear to me what you're asking for particularly.

And I think, would be cool to allow build scripts to build the:

• library only (don't build tools)

make libfluidsynth and the executable won't be compiled.

• for some other cases, disable some parts of the library such as the built-in MIDI sequencer or some other, keeping real-time MIDI API only

The MIDI sequencer is an integral part of fluidsynth that has no special dependencies. Stripping it away would mean to make severe parts of fluidsynth API inoperateable. This won't happen.

• disable audio output devices support, keep only raw output PCM/float calls to let developer handle all audio output by theme selves.

See the enable-xxx cmake options.

• etc.

?

[Wohlstand]

Fluidsynth doesn't have an "Autotools builder". The one and only build system is CMake.

I see, just hadn't paid attention it no longer exists, that should be fine, I didn't like Autotools because of tricky usage and limitations (such as no support of BSD Make, which is a problem for macOS and x-BSD, and no way to use Ninja as a more effective builder than GNU Make).

tools

By tools, I meant that executable, I wanted to just build the library only without executable.

make libfluidsynth and the executable won't be compiled.

I see, but when repo build is attached as a subdirectory, will need to use workarounds such as excluding from "all" unneeded parts. Also, the exclusion of executable by the build side should also disable any dependency checks at the CMake side. That is also needed if trying to build the library for non-standard platforms which lack all these dependencies.

The MIDI sequencer is an integral part of fluidsynth that has no special dependencies. Stripping it away would mean to make severe parts of fluidsynth API inoperateable. This won't happen.

By the fact, that this is fine, let the MIDI sequencer stay here always.

See the enable-xxx cmake options.

Yes, there is a lot of them. But I would have one option that disables all of them at once. Also, this flag should handle any future additions that will be done in the future (like adding support for new potential audio output, etc.).

Anyway, I would get a shot at free time to add all necessary changes to make a lightweight build easier to build and post the pull request. But before, I want to ask, do you like this idea?

[derselbst]

But I would have one option that disables all of them at once.

This flag would be redundant to the other existing flags. We had such a redundant flag in the past "enable-debug" which was conflicting with "CMAKE_BUILD_TYPE". We removed it in the end.

Also, this flag should handle any future additions that will be done in the future

I don't like functionality that only serves for "lazy purposes", sry. If someone wants a lightweight build, I would expect him to take 10 minutes and see how this can be achieved. Also, if anything new would be added, you would have to actively install the necessary dependency libraries and headers to make it work. And something "new" is only added upon minor version bumps, which is easy to recognize as well. So sorry, I don't really like this idea.

However, I have no strong opinion on adding yet another flag that would disable compiling the executable. I don't see a real benefit in doing so, but it wouldn't hurt either.