Porting a library made on Windows (32bit) to Mac (64bit)

augustoest

Porting a library made on Windows (32bit) to Mac (64bit)

in Library and Tool Development • 3 years ago

Hello,

Some time ago I developed a Processing library to ease the work with touchatag RFID readers ( http://forum.processing.org/#Topic/25080000000014013). Since this library only work in Windows, I've now decided to port it to Mac.

Problem is, I'm pretty new to MacOS. The library I developed used libnfc. I basically compiled libnfc and added the resulting .dll and .lib to my Visual Studio project. I'm wondering what do I need to add to Xcode (is Xcode the best way to go, or should I use Eclipse or Netbeans?), since we don't have .dlls on the Mac.

Replies(8)

PhiLho

Re: Porting a library made on Windows to Mac

3 years ago

I know next to nothing to Mac dev, but I believe that since Macs are Unix boxes, you probably want to generate .so files. Google for shared libraries.

augustoest

Re: Re: Porting a library made on Windows to Mac

3 years ago

It appears that Macs use dylib's. I also chose to try this over Eclipse instead of Xcode.

I basically compiled libnfc, which generated a folder ( lib) with dylib files (one of it being the libnfc.dylib), and an nfc folder with three headers.

I copied both folders into my project's folder ( touchatag), and I then went to the Project's preferences, C/C++ Build, Settings, GCC C Compiler, Directories, and added:

"${workspace_loc:/touchatag/nfc}"

/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/JavaVM.framework/Versions/A/Headers (this is because of JNI, but that's another story)

I also went to the Project's preferences, C/C++ Build, Settings, MacOS X C Linker, Library search path:

"${workspace_loc:/touchatag/lib}"

And in the Project's preferences, C/C++ Build, Settings, MacOS X C Linker, Libraries: libnfc.dylib

As for the output, I went to the Project's preferences, C/C++ Build, Settings, Build Artifact, and chose:

Artifact Type: Shared Library

Artifact name: touchatag

Artifact extension: dylib

Output prefix: lib

But, when I run everything:

**** Build of configuration Release for project touchatag ****
make all
ld: library not found for -llibnfc.dylib
collect2: ld returned 1 exit status
make: *** [libtouchatag.dylib] Error 1
Building target: libtouchatag.dylib Invoking: MacOS X C Linker
gcc -nostartfiles -nodefaultlibs -L"/Users/augustoesteves/Documents/workspace/touchatag/lib" -dynamiclib -o "libtouchatag.dylib" ./touchatag.o -llibnfc.dylib

Any clues? :/

PhiLho

Re: Porting a library made on Windows to Mac

3 years ago

OK, another uninformed advice...

I would try and remove double quotes. So you have a command line looking like:
gcc -nostartfiles -nodefaultlibs -L/Users/augustoesteves/Documents/workspace/touchatag/lib -dynamiclib -o libtouchatag.dylib ./touchatag.o -llibnfc.dylib
Again, in classical Unices, quoting paths is done with single quotes, and isn't necessary if they have no special chars (spaces, starting with dash, etc.).

augustoest

Re: Re: Porting a library made on Windows to Mac

3 years ago

I've removed the "" from "${workspace_loc:/touchatag/lib}", etc

I also changed my Project's preferences, C/C++ Build, Settings, MacOS X C Linker, Libraries from libnfc.dylib to nfc, since someone mentioned -lnfc. Now I'm getting:

make all
Building file: ../touchatag.c
Invoking: GCC C Compiler
gcc -I"/Users/augustoesteves/Documents/workspace/touchatag/nfc" -I/Developer/SDKs/MacOSX10.6.sdk/System/Library/Frameworks/JavaVM.framework/Versions/A/Headers -O3 -Wall -c -fmessage-length=0 -MMD -MP -MF"touchatag.d" -MT"touchatag.d" -o"touchatag.o" "../touchatag.c"
../touchatag.c: In function 'Java_touchatag_Touchatag_nativeTagID':
../touchatag.c:78: warning: passing argument 1 of '__builtin___strcpy_chk' from incompatible pointer type
../touchatag.c:78: warning: passing argument 1 of '__inline_strcpy_chk' from incompatible pointer type
../touchatag.c:86: warning: passing argument 2 of '(*env)->NewStringUTF' from incompatible pointer type
Finished building: ../touchatag.c
Building target: libtouchatag.dylib
Invoking: MacOS X C Linker
gcc -nostartfiles -nodefaultlibs -L"/Users/augustoesteves/Documents/workspace/touchatag/lib" -dynamiclib -o "libtouchatag.dylib" ./touchatag.o -lnfc
Undefined symbols:
"___stack_chk_guard", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"_malloc", referenced from:
_Java_touchatag_Touchatag_nativeConnectedRFID in touchatag.o
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"___sprintf_chk", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"___stack_chk_fail", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"_free", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"___strcat_chk", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
"_strcpy", referenced from:
_Java_touchatag_Touchatag_nativeTagID in touchatag.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [libtouchatag.dylib] Error 1

augustoest

Re: Porting a library made on Windows to Mac

3 years ago

I've unchecked an option in the Eclipse (it wasn't loading the default libraries) and now I managed to compile the libtouchatag.dylib.

I've then moved to write my Java code to create my Processing library. I've copied all the files in the libnfc's lib folder, as well as my newly compiled libtouchatag.dylib. I call both these libraries from Java with:

static {
System.loadLibrary("nfc");
System.loadLibrary("touchatag");
}

Everything builds ok, but when I try to run a Processing example that uses the resulting library, I get:

processing.app.debug.RunnerException: UnsatisfiedLinkError: /Users/augustoesteves/Documents/Processing/libraries/touchatag/library/libnfc.dylib: no suitable image found.

Did find: /Users/augustoesteves/Documents/Processing/libraries/touchatag/library/libnfc.dylib: mach-o, but wrong architecture

augustoest

Re: Porting a library made on Windows to Mac

3 years ago

It seems this error is because both libnfc and libtouchatch have a 64bit architecture (x86_64), and I'm assuming the Processing sketch don't. Any ideas on how to solve this? :/

augustoest

Re: Porting a library made on Windows (32bit) to Mac (64bit)

3 years ago

I tried compiling libnfc as a 32 bit library, by doing:

sudo make CFLAGS='-arch i686' LDFLAGS='-arch i686' CC='gcc -m32' CXX='g++ -m32'

But it clashes with libusb:

d: warning: in /usr/local/Cellar/libusb-compat/0.1.3/lib/libusb.dylib, file was built for unsupported file format which is not the architecture being linked (i386)

augustoest

Re: Porting a library made on Windows (32bit) to Mac (64bit)

3 years ago

Compiled my library, libusb, libnfc, and libusb-compact in i386. Works now :)

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