Symbol not found error integrating BASS audio library with ffigen

[JimTompkins]

I'm trying to integrate the BASS audio dynamic library for iOS from un4seen Developments with Flutter. I've started a Flutter FFI plugin that can be found here. It uses ffigen to convert the bass.h file to generated_bindings.dart.

Here is a snippet from generated_bindings.dart:

  int BASS_Init(
    int device,
    int freq,
    int flags,
    ffi.Pointer<ffi.Void> win,
    ffi.Pointer<ffi.Void> dsguid,
  ) {
    return _BASS_Init(
      device,
      freq,
      flags,
      win,
      dsguid,
    );
  }

  late final _BASS_InitPtr = _lookup<
      ffi.NativeFunction<
          BOOL Function(ffi.Int32, DWORD, DWORD, ffi.Pointer<ffi.Void>,
              ffi.Pointer<ffi.Void>)>>('_BASS_Init');
  late final _BASS_Init = _BASS_InitPtr.asFunction<
      int Function(
          int, int, int, ffi.Pointer<ffi.Void>, ffi.Pointer<ffi.Void>)>();

It builds (Flutter 3.3, XCode 14, ffigen 6.1.2) but throws a run-time error when I try to call the BASS_init function: Failed to lookup symbol '_BASS_Init': dlsym(0x100f61e18, _BASS_Init): symbol not found

I can see the symbol in the libbass.a file using nm -gU libbass.a

I added the following frameworks to the Xcode build: AVFoundation, AudioToolbox, SystemConfiguration, CFNetwork, Accelerate In Xcode by going to Build Phase-->Link Binary with Libraries-->Add This did not make any difference i.e. still getting symbol error

I checked that “Enable bitcode” is set to “No” in Xcode under Build Settings-->Build Options.

Any comments/suggestions greatly appreciated!

[dcharkes]

I have a setup locally with xcframeworks

ios/mylib_staticlib.podspec:

  s.pod_target_xcconfig = {
    'DEFINES_MODULE' => 'YES',
    'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386',
    "OTHER_LDFLAGS[sdk=iphoneos*]" => "-force_load $(PODS_TARGET_SRCROOT)/Frameworks/mylib_staticlib.xcframework/ios-arm64_armv7/libmylib_staticlib.a",
    "OTHER_LDFLAGS[sdk=iphonesimulator*]" => "-force_load $(PODS_TARGET_SRCROOT)/Frameworks/mylib_staticlib.xcframework/ios-arm64_x86_64-simulator/libmylib_staticlib.a",
  }
  s.vendored_frameworks = 'Frameworks/mylib_staticlib.xcframework'
  s.swift_version = '5.0'

ios/Classes/dummy_file.c

// A dummy file so that the mylib_staticlib.framework is created.

.a files should work as well, but then the podspec is:

s.pod_target_xcconfig = {
--
  | 'DEFINES_MODULE' => 'YES',
  | 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64',
  | "OTHER_LDFLAGS" => "-force_load $(PODS_TARGET_SRCROOT)/Frameworks/libmylib_staticlib.a"
  | }
  | s.vendored_libraries = 'Frameworks/libmylib_staticlib.a'

Other things to double check:

• Is the .a file for the right architecture?

P.S. This is not an ffigen issue, the bindings are not wrong.
This is a question with Flutter FFI plugins, and belongs on the Flutter repo (or StackOverflow).

[JimTompkins]

Thanks for that hint! I'm trying to use a static library, so I tried adding these two lines to my podspec file:

s.pod_target_xcconfig = {'DEFINES_MODULE' => 'YES', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386', "OTHER_LDFLAGS" => '-force_load ($SRCROOT)/../../../ios/bass24-ios/bass.xcframework/ios-arm64_armv7_armv7s/libbass.a' } s.vendored_libraries = '($SRCROOT)/../../../ios/bass24-ios/bass.xcframework/ios-arm64_armv7_armv7s/libbass.a'

but I get a file not found error:

Could not build the precompiled application for the device.

Error (Xcode): File not found:

(/Users/jimtompkins/git/flutter_bass/example/ios/Pods)/../../../ios/bass24-ios/bass.xcframework/ios-arm64_armv7_armv7s/libbass.a

But the .a file is at that location:

% ls -als /Users/jimtompkins/git/flutter_bass/example/ios/Pods/../../../ios/bass24-ios/bass.xcframework/ios-arm64_armv7_armv7s/libbass.a                                     


1536 -rw-r--r--@ 1 jimtompkins  staff  785096  8 Sep  2021 /Users/jimtompkins/git/flutter_bass/example/ios/Pods/../../../ios/bass24-ios/bass.xcframework/ios-arm64_armv7_armv7s/libbass.a

Apologies for what feels like a newbie question now...

Thanks!

[JimTompkins]

Found that the ( ) around $SRCROOT in the -force_load were causing the problem.