Suppose I've read this caveat, and I still want to use TBB as a statically-linked library. (Pretend I'm working in an environment where users aren't allowed to create their own dylibs.) But I don't really want to rewrite the TBB makefile to generate libtbb.a instead of libtbb.dylib.
Is there a simple command-line way to convert libtbb.dylib into libtbb.o with the same entry points?
I have heard a good argument for not being able to go the other way, from static to dynamic. Namely: dynamic libraries need to be PIC, and converting a non-PIC static library to PIC isn't feasible. But that argument doesn't apply in the other direction, as far as I know.
Here's someone saying it's impossible to convert .dll to .a on Windows, but I think they're just talking about the impossibility of breaking a .dll or .exe back up into its original .o files, not necessarily saying it would be impossible to create a linkable .o file with the same contents. Also, the situation on Windows is slightly odder than "real" PIC, although I don't think that's relevant.
Intel Threading Building Blocks (TBB) is available as binary for Windows, Mac and Linux. If you expect to use libtbb.dylib from the Mac distribution on iOS then you are out of luck. The Mac distribution is targeted for Intel (32 and 64 bits). Since iOS runs on ARM processors, you could not use it, even if you found a way to convert a dynamic library to a static library.
If you found a libtbb.dylib file somewhere else targeted for ARM, then you could probably use it on iOS. It's actually possible to load dynamic libraries on iOS. Have a look at the dlopen(3) man page.
Finally, you should read about Grand Central Dispatch (GCD) instead, which is built-in support for concurrent code execution on multicore hardware in iOS and OS X.
Related
I'm very interested in using GStreamer's iOS framework http://docs.gstreamer.com/display/GstSDK/Installing+for+iOS+development for video streaming, but when I add the framework to a blank project and add a few lines of code to take advantage of its powerful features, the final IPA is 27MB. This is just way to big to be adding to my project, what is the best way to go about stripping this down the the bare necessities as I'm sure I'm only using a small percent of the code that is included in the SDK.
Here's a pic showing the package contents of the IPA:
Thanks!
In the gst_ios_main.h you can disable all the plugins that you don't need (make sure to enable linker optimizations so that unused code is removed). If that's not enough, you can build your own stripped down version of the iOS binaries with http://cgit.freedesktop.org/gstreamer/cerbero/ (you need to remove things from the .package and .recipe files to only build what you need). Just disabling things from gst_ios_main.h should be enough in 99% of the cases though.
Note that by default you'll build applications for multiple architectures, as such the resulting application will be rather large. Depending on your use case you can drop some architectures.
On another note, gstreamer.com is providing an completely outdated version of GStreamer and is in no way related to the GStreamer project. The official website is http://gstreamer.freedesktop.org .
SDKs have their source code encapsulated away from you, the user. You get access only to header files. Thus you just can't extract some class from it because you don't have access to the implementation file.
Of course if this library is opensource you can attempt to isolate one class, but sometimes everything is so deeply connected, that it is close to impossible.
I need to compute MSB (most significant bit) on millions of 32-bit integers on iPad very fast. I have my own (ugly) implementation of MSB written on plain C, which is slow. ARM processors have CLZ (count leading zeroes) hardware command, which can be very useful for that. According to ARM reference there is an intrinsic C function __CLZ. How can I add support of ARM intrinsic functions to my Xcode project?
P.S. I've managed to find the way of accessing hardware CLZ from NEON (by including arm_neon.h), but that's not what I need, because it's only works with vector, but I need scalar MSB.
I found ARM intrinsic functions names on page 44 of ARM C language extensions. Some of them works in Xcode. This prints 31, as expected:
NSLog(#"%u", __builtin_clz(1));
Notes:
I haven't found any references of this in Apple docs. Most likely Xcode inherited those functions from LLVM or CLANG.
You don't need to include any special headers or frameworks to use those functions. Xcode IDE autocomplete doesn't know about them.
Only a few functions from extensions list are implemented. According to pages 12-13 of the same document it should be two header files: arm_acle.h for non-NEON intrinsics and arm_neon.h for NEON intrinsics. Xcode have only the second file, but some of the functions from the first file declared somewhere else.
This may be obvious, but if if you use ARM-specific instructions, you will not be able to run your app in the iOS simulator. The simulator uses the native x86-64 hardware of your Mac.
You could create a wrapper function that uses a compiler directive to use the ARM command or fall back to the "ugly" code if you don't have support.
I have been given a Shared Object file (.so) and the functions inside of it, but I don't have a clue as to how to use it, or alter it for use in an iOS application. Could someone point me in the right direction?
I know the .so came from an Android application, but I was told I could get it to work in an iOS application as well.
Actually and technically, yes, you can, but not in a way you would ever think.
If it came from Android, it is probably compiled for ARM. So it should be binary-compatible with the ARM CPU in iOS devices. However, iOS doesn't use the usual format of shared objects (that is, the ELF format), but iOS' and OS X's own Mach-O format.
This means that you cannot directly link against this shared object file nor are you able pass it directly to dlopen() and dlsym(). You have to get into serious hacking (something that you probably don't know). This involves loading and relocating the file properly.
An example of this can be found in iOS jailbreak developer and hacker, Comex's GitHub repository Frash, a Flash player for jailbroken iOS devices. Comex essentially wrote an ELF loader module (dubbed "food") for iOS and used it to make Android's libflashplayer.so work on iOS. Pretty neat, huh?
Also note that this is not going to be possible for AppStore apps as it needs dynamic loading and various alterations in the OS.
while technically possible (see h2co3's answer) for anything practical the answer is no
so files arent in the correct binary format
even if they were, dynamic loading is not allowed by appstore
I have a C lib and dll file from windows application. No source code with me.
Is it possible to use that in an IOS application.
I have seen mixed responses and am confused.
If we have source code , i think we need to create dylib and then we can use the same after including relevant header file.
Please share any expert ideas to guide me in right direction.
Appreciate your help .
mia
Dynamic Libraries are not permitted on iOS to begin with, but above that, the DLL file format is not recognized by Darwin or the underlying XNU Kernel at all, as the binary format is different.
Windows APIs are not usable on the Darwin OS either (Both Mac OS X and iOS are wrappers around the basic Darwin OS). You will need to rewrite the code from the DLL to use the POSIX and/or Objective-C APIs and compile it as a static library to use it.
You need to get a iOS compatible library, no other way around it. There are several reasons:
iOS doesn't support DLLs as they are windows format, but moreover, you can't use any dynamic library on iOS, as Apple restricts it.
DLLs are usually for intel CPUs, while iOS devices have ARM CPUs.
Most dlls are calling windows APIs - are you sure this one's not?
No. If you all you have is a compiled binary DLL, there is no way to use it on iOS. Unless you happen to have an ARM DLL for the upcoming Windows 8, your DLL contains either x86 or x86-64 machine code (or maybe IA64 if you have a lot of money), which absolutely will not run on iOS devices, which are all ARM architectures. Plus many more reasons.
If you have the source code, you can recompile it for iOS, either directly into your app, as a static library that can be linked in with your app, or as a dynamic library as part of a framework. But in all cases, you need to recompile it from source code using the iOS compiler.
You are going to have to recompile it as a static library (.a file). Apple doesn't allow dynamic libraries except for their own frameworks (so you can't compile it as a dylib).
Has anyone used Bluetooth on Mac OS X with Lazarus or FreePascal? There is a bluetooth unit, but it currently only supports Linux.
Information about existing unit:
http://wiki.freepascal.org/Bluetooth
I plan to enhance this to support Mac OS, but it would be nice to know if anyone has written any code to use BlueTooth on Mac OS already to avoid duplicated work.
On the other hand, if you have used XCode to access Bluetooth, what libraries did you use? I am sure I can discover this with the XCode profiler by opening some Bluetooth applications.
Note: Mac OS X doesn't appear to use the BlueZ library that Linux has, so I don't think the solution is as easy as changing the library path. Instead, it has IOBluetooth "Framework", located at /System/Library/Frameworks/IOBluetooth.framework.
Having a look, it looks like:
kaikei.ocn.ntt.com:IOBluetooth.framework $ file *
CodeResources: XML document text
Headers: directory
IOBluetooth: Mach-O universal binary with 3 architectures
IOBluetooth (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64
IOBluetooth (for architecture i386): Mach-O dynamically linked shared library i386
IOBluetooth (for architecture ppc7400): Mach-O dynamically linked shared library ppc
Resources: directory
Versions: directory
On the other hand, I think if anyone had done this already, I would probably be able to find it on Google.... On the off chance I am wrong, please reply and let me know.
Clarification: I have created bindings for normal shared libraries before (f.e. sqlite3), but not for a "framework". If nobody has created bindings or otherwise used the MacOS Bluetooth framework from FreePascal, advice on how to use framework functions from FreePascal in general woule be appreciated. (And normally the functions I am porting are C based, not Obj-C, so I am not sure how to declare Obj-C methods in FPK, although I am sure I will be able to find some samples if I keep searching).
The main svn repository for translated Mac OS X framework C headers is http://svn.freepascal.org/svn/macosxintf/trunk
From time to time, FPC releases are synchronised with the latest versions hosted there. Note that the files in that repository (in the MPPInterfaces subdirectory) are in a generic format that can be automatically translated into either FPC, GPC or CodeWarrior Pascal versions.
To generate the FPC versions, use "make fpcpinterfaces", and find the results in the Build/FPCPinterfaces folder.
To translate new headers, execute something like this from inside a checked out copy of the macosxintf repository:
./Scripts/Convert.pl /System/Library/Frameworks/IOBluetooth.framework/Headers/IOBluetooth.h FORCE MPPInterfaces
Afterwards, you'll still have to edit the resulting file to add/remove units and clean up some other things not handled by the automatic translation process. Once finished, you may want to submit a bug report at bugs.freepascal.org with the finished units.
(note: because I'm unregistered, I can only add in one url per post, so the next url's are a bit mangled to get around that restriction)
You can also subscribe to the Mac Pascal list (lists.sonic.net/mailman/listinfo/mac-pascal) and ask there whether someone already translated those headers.
The Bluetooth framework indeed also contains some Objective-C headers. Objective-Pascal support is only available in the latest FPC svn versions, as described on the FPC wiki (google FPC_PasCocoa). You need this support in order to interface with Objective-C.
Translating Objective-C is probably easiest using the script elsewhere in FPC's svn (svn.freepascal.org/svn/fpc/trunk/packages/cocoaint/utils/)
You may want to ask for help on the above-mentioned Mac Pascal list, as all people maintaining the aforementioned translations and translation tools are subscribed there.