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9163 :: How to build a static library after nimble install?

• planetis (orginal) [2022-05-19T20:14:50+02:00] view original

  All I need is to clone the repository, build the static library and copy it and the C header file in a directory that can be found by the Nim bindings, so probably within the nimble path mylib? It should take a user specified argument about the target platform. I would also like to be able to get the correct path without user intervention. Should I avoid installing it globally or not?! What happens on Windows?

  Using a nimble task or a nimscript file from the client package proved problematic because I can't get the path to the installed library. mymodule.nims wouldn't execute when importing mymodule. A library nimble task doesn't look like it takes parameters but I guess I could resort to defining multiple tasks like buildAndroid, buildDesktop. Any examples I can use? Or better alternatives?

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• ggibson (orginal) [2022-05-19T20:24:03+02:00] view original

  Maybe add a step in your nims file to build the library? --app:lib should do it. This will make different files depending on the OS, as you point out. Then, add a .nim source file in your nimble installed module that can be imported. Make this file link with the compiled library that is locally found through the appropriate global-scope pragmas (I forget what they are). In this way you can import yourmodule as a nim binding, and have code in your module determine which operating system you're on, and then link with the correct name for the generated lib, no matter where nimble installs things.

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• planetis (orginal) [2022-05-19T20:31:29+02:00] view original

  Maybe add a step in your nims file to build the library? --app:lib should do it.

  Actually I've built a wrapper for a C library. It is that library I need to clone and place next to the Nim bindings.

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• ggibson (orginal) [2022-05-20T02:53:07+02:00] view original

  Can you list the full series of commands you wish would yield what you want from start to finish? I don't quite understand why you can't follow the same module pattern as https://github.com/genotrance/nimssl, which downloads a c library and yields bindings to it.

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• demotomohiro (orginal) [2022-05-20T06:22:41+02:00] view original

  I don't know what C library you are wrapping but your nimble package always need to build static library even if the C library is already installed? Let users install the C library using system package manager or other package mananer like Conan or MSYS2 is not an option? Can we choose whether your nimble package use already installed C library or build C library when installing it?

  I think you should avoid install c libraries globally. On most of linux, files in /lib, /usr/include or /usr/lib are managed by package manager and copying files that doesn't managed by package manager might cause problems. On windows, as far as I know, there is no such standard directories for include files or static link libraries. People can install GCC in random path on windows.

  This article about C library might help you: https://internet-of-tomohiro.netlify.app/nim/clibrary.en.html

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• ynfle (orginal) [2022-05-20T08:27:26+02:00] view original

  (Great article, by the way)

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• planetis (orginal) [2022-05-20T09:06:34+02:00] view original

  Thanks both of you! I will study the examples you gave me. Much appreciated!

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• planetis (orginal) [2022-05-20T10:15:32+02:00] view original

  @ggbison Actually I have done all the steps you mentioned. It's just that nimble is giving a hard time to provide a package that does all these semi-automatically. The user still needs to specify the platform they want to develop against, the available options, for now, are Desktop, RPi, DRM and Android. I can't get how nimssl is supposed to work. I see this error log

  
  stack trace: (most recent call last)
  /tmp/nimblecache-3067454014/nimscriptapi_1623384115.nim(208, 29)
  /tmp/nimble_11746/githubcom_genotrancenimssl/nimssl.nimble(27, 12) installBefore
  /tmp/nimble_11746/githubcom_genotrancenimssl/nimssl.nimble(24, 8) setupTask
  Nim/lib/system/nimscript.nim(264, 7) exec
  Nim/lib/system/nimscript.nim(264, 7) Error: unhandled exception: FAILED: nimgen nimssl.cfg [OSError]
         Tip: 5 messages have been suppressed, use --verbose to show them.
  nimscriptwrapper.nim(160) execScript
  Run

  But nimssl.nimble doesn't have any tasks, so how are those called? I guess one of the dependencies creates nimssl.cfg? Using nimble is so confusing.

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• planetis (orginal) [2022-05-20T10:20:07+02:00] view original

  Thanks for explaining the basics, it is much clearer for me now. I chose to always link against a static library instead of dynamic linking with the globally installed library. It's much simpler for me to keep it that way. I will probably switch back to nake tasks and require the user to cd into the installed directory and running nake tasks It's much simpler than the mess I have ended up with and it worked.

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