I am integrating opencv2.framework with my project. I did the following steps for completion.
Added opencv2.framework to "Linked Frameworks and Libraries"
Added libc++.dylib to "Linked Frameworks and Libraries"
Added following code to AppName-Prefix.pch file
#ifdef __cplusplus
#import "opencv2/opencv.hpp"
#endif
Changed compiler default of
Apple LLVM compiler 4.2 - Language -> C++ Language Dialect -> GNU++11 [-std=gnu++11]
C++ Standard Library -> libc++ (LLVM C++ standard libray with C++ 11 support)
Still I am getting a link error which is saying
"opencv2.framework/opencv2(surf.o)
ld: 21 duplicate symbols for architecture armv7"
Can anyone help me on this?
EDIT:
My XCode version is 4.6, IOS SDK is 6.1 and deployment target is 4.3 (I tested with 5.0 also, but not working in that target too)
Update: github pull request which fixes this issue is now merged to OpenCV.
Cause:
In OpenCV source, there are two files named 1. surf.cpp and 2. surf.ocl.cpp which results in two surf.o object files for each architecture inside opencv framework library.
Fix:
In OpenCV source, apply patch from github pull request
and Build OpenCV for iOS.
See: Use lipo on OpenCV to extract separate libs for each architecture ( armv7, armv7s and i386 ) and then use ar -tv to see two object files of same size with name surf.o
I don't know: Only some XCode projects fails with the pre built OpenCV framework. I use Xcode 5.0 with OpenCV 2.4.6.1. Can this be fixed with some XCode build setting ?
Related
When I tried to compile my XCode project with OpenCV 2.4 iOS using XCode 7 + iOS SDK 9, XCode complained that
ld:
'opencv2.framework/opencv2(alloc.o)'
does not contain bitcode. You must rebuild it with bitcode enabled
(Xcode setting ENABLE_BITCODE), obtain an updated library from the
vendor, or disable bitcode for this target. for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
and refused to link. After some googling, it turns out to be because Apple added a new feature named Bitcode for app optimization within App Store. While OpenCV iOS binary hasn't been updated to include Bitcode, it cannot pass the link stage.
Some reference pointed out a temporary solution to disable ENABLE_BITCODE so the linking could be done without Bitcode. This will prevent the app being compiled for Apple Watches because Bitcode is mandatory for Watch Apps. Therefore my question is, are there some (best easy) ways to compile iOS OpenCV with Bitcode enabled? (better with a download link for compiled framework)
After some search and trial, I figured out a way to compile OpenCV iOS from the source with Bitcode. A compiled binary is also provided here: [v3.0] [v2.4]. [Disclaimer: I am not responsible for the integrity of the compiled binary. Use at your own risk.]
The steps of compilation is basically the same as the official document, with only one extra step.
Download the code with git:
cd ~/<my_working_directory>
git clone https://github.com/Itseez/opencv.git
Make symbolic link for Xcode to let OpenCV build scripts find the compiler, header files etc.
cd /
sudo ln -s /Applications/Xcode.app/Contents/Developer Developer
[Key Step] Change the compilation script to add the extra option for Bitcode: edit ~/<my_working_directory>/opencv/platform/ios/build_framework.py, and locate the line containing -DCMAKE_C_FLAGS. Add a flag of -fembed-bitcode. For example, in the source I got, it's line 55, and will look like
"-DCMAKE_C_FLAGS=\"-Wno-implicit-function-declaration -fembed-bitcode\" " +
after the change. [ref]
Build OpenCV framework:
cd ~/<my_working_directory>
python opencv/platforms/ios/build_framework.py ios
If everything’s fine, a few minutes later you will get ~/<my_working_directory>/ios/opencv2.framework. You can add this framework to your Xcode projects.
P.S. Ask a question, even when you already know the answer is encouraged according to this post on Meta Stackchange.
OpenCV is precisely the kind of software (along with audio and video Codecs) that is likely to have hand-rolled ARM NEON optimisations. The documentation suggests that ~40 functions have had this treatment in OpenCV3.0.
If compiling for LLVM bit-code you'll get the generic (less optimised, implemented in C or C++) versions instead.
Use of Bitcode is optional - except when compiling for Apple watch, where it's hard to imagine you'd run computationally complex image processing anyway. If you're bundling a watch app, override the build setting for bitcode on it only.
For the recent couple of days I have had this compiler error in Xcode every time I've built my project:
ld: warning: ignoring file /.../(Framework Name).framework/(Framework), missing required architecture x86_64 in file /.../(Framework Name).framework/(Framework) (2 slices)
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_CLSNAME", referenced from:
objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I also can't run this code on the iPhone 5 simulator (i386).
The iPhone device I have is outdated and can't run iOS 8. I tried setting the build settings to iOS 7 but I get an error regarding the lack of support for dynamic libraries before iOS 8.
Things to note:
I am using 2 projects, in 2 different workspaces. (one for the library and one for the demo app. Tests of the same code with the unit tests in the library project are successful.)
I used to be able to link the demo project with the library project until I had to do some changes in the library code. After I exported the newer version this error started occurring.
In order to get the library file/folder (.framework) I used the Archive option.
Running lipo -info outputs Architectures in the fat file: lib.a armv7 arm64
I have C++ code in the library project (unlikely to be the issue)
In the library project, I am using another external library I installed with Cocoa Pods (also used to work before changes in the library code)
Solutions I tried:
Changing the Architectures and the Valid Architectures list in Build Settings.
Setting "Build Active Architecture Only" to "No" in Build Settings.
Creating a new project (both for the demo and the library)
Making the library a static library (new project, got the same warning, no error, couldn't #import the files I needed)
I only started working with iOS and Xcode a couple of months ago and I am not super-experienced with everything there yet, so please try to explain everything with as much detail as you can.
Thanks in advance to anyone trying to help :)
Did you add the framework it says is missing? Also, try to delete the Derived Data folder and then clean the project. If that does not work, then turn off Modules in build settings.
I've gone through the various solutions of compiling libical v1.0 for armv7, however the latest libical library available on github seems to have moved to cmake:
https://github.com/libical/libical
Can someone please guide me as to what I should be doing to get this to compile for iOS and Mac (one fat static library)? I've been able to compile it for the Mac but don't know how to do the same for armv7 and arm64. Thanks!
I tried everything from ios-toolchain for cmake to writing a build script myself. Nothing worked. In the end it turned out to be simple. Simply run cmake and compile libical on a 64-bit Mac. Then take all the produced code from under the "src" directory and add that straight to your iOS project. Then, replace #include with #include "config.h" globally and disable ICU support. Add a preprocessor macro to your build settings to include the generated config.h
I created my own iOS framework by following this tutorial, https://code.google.com/p/ios-static-framework/, which uses a static library template and aggregate target with a custom run script to create a framework.
At first it works fine. After including another library in the framework project creates the error when archive or build for device. I think the problem is with some wrong settings for that library. But I just don't know what to try. I have tried setting some sensible Other Linker Flags from https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/ld.1.html , but no luck. Can anyone help please ;(
What steps will reproduce the problem?
Follow the tutorial, but change the Aggregate script architecture from armv6 armv7 to armv7 armv7s. Here is the part of the aggregate target script I changed. Everything else is the same.
if [[ "$SF_SDK_PLATFORM" = "iphoneos" ]]
then
SF_OTHER_PLATFORM=iphonesimulator
SF_ARCHS=i386
else
SF_OTHER_PLATFORM=iphoneos
SF_ARCHS="armv7 armv7s"
fi
Add an external library to the project, here I use libBlocksKit.a.
Build the framework, success.
In another child project. Include my built framework.
Add -ObjC in the app Target > Build Settings > Other Linker Flags
Archive and get error. Building for device (iPhone5) gives error too. But building for simulator seems to work.
What is the error?
This error, basically "ld: warning: directory not found for option ... ld: lto: could not merge in ... symbol multiply defined!".
ld: warning: directory not found for option '-L/Users/hlung/Dropbox/- Notes/stackoverflow/RealFrameworkApp/RealFrameworkApp/External/BlocksKit'
ld: lto: could not merge in /Users/hlung/Library/Developer/Xcode/DerivedData/RealFrameworkTest-evagqzwzyyolhjenkkjbvzibxppf/Build/Products/Debug-iphonesimulator/RealFrameworkTest.framework/RealFrameworkTest(NSObject+BlockObservation.o) because 'Linking globals named 'OBJC_CLASS_$_BKObserver': symbol multiply defined!', using libLTO version 'LLVM version 3.2svn, from Apple Clang 4.2 (build 425.0.28)' for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
If I archive my child project with only one architecture (like armv7), it works. It shows this error with armv7 armv7s architectures ( $(ARCHS_STANDARD_32_BIT) ).
What version of the product are you using? On what operating system?
OS X 10.8.5, XCode 4.6.3
== Update 1 ==
Posted an issue at the tutorial's code.google.com page Update: 2 weeks no answer.
I found a set of useful suggestions from this answer. Update: Doesn't work
I have created a project so you can run and see for yourself here
Linking against a static library from within a framework can create some interesting challenges... It sounds like you may be linking to BlocksKit from both your framework and your application projects.
You should link in only one of those places. Try removing libBlocksKit.a from the Link Libraries build phase of your framework, but leave it in the other project.
You can do like this:
Click on your project (targets)
Click on Build Settings
Under Library Search Paths, delete the paths
I hope it can help you.
My project was working just fine until this morning. I was using xcode 4.3, and an older version of OpenCV (I'm not sure about the exact version). OSX was already 10.7.x, but not 10.7.5
Today, after upgrading OSX to 10.7.5, xcode to 4.5.2, and downloading OpenCV 2.4.3, I am getting the following linker errors when trying to build the project:
Undefined symbols for architecture armv7:
"_OBJC_CLASS_$_ALAssetsLibrary", referenced from:
objc-class-ref in opencv2(cap_ios_video_camera.o)
"cv::FeatureDetector::create(std::string const&)", referenced from:
-[ImageAnalyzer detectBlobs:] in ImageAnalyzer.o
"cv::FeatureDetector::detect(cv::Mat const&, std::vector >&, cv::Mat const&) const", referenced from:
-[ImageAnalyzer detectBlobs:] in ImageAnalyzer.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
In order to use the new opencv framework I removed the reference to the old framework, and referenced the project to the official prebuilt opencv2.framework downloaded from here.
I also removed the reference to libz.dylib, and added a reference to libc++.dylib instead.
Last step was to update the prefix file to the new framework. The relevant part in the prefix file now looks like this:
#ifdef __cplusplus
#import <opencv2/opencv.hpp>
#endif
It all narrowed down to these 4 linker errors I can't seem to get rid of. I tried using libstdc++.dylib, but I am getting even more errors. I also tried building OpenCV myself as explained here, but I am still getting the same errors as the prebuilt framework.
What did I miss? Is there anything else I need to change in my project?
UPDATE:
As seen here, setting the "C++ Standard Library" to "libc++ (LLVM C++ standard libray with C++ 11 support" yielded only one error:
clang: error: invalid deployment target for -stdlib=libc++ (requires iOS 5.0 or later)
Changing the deployment target to iOS 5 finally got my project to run again.
Does this mean OpenCV 2.4.3 doesn't work on iOS versions older than 5?
steps to compile and run c++ opencv 2.4.4 on mac os x lion 10.7.5 with cmake 2.8.10 and xcode 4.6.1
Having the right tools
download opencv-unix from http://sourceforge.net/projects/opencvlibrary/files/ and untar it wherever
download cmake .dmg from http://www.cmake.org/cmake/resources/software.html and install it
i am assuming you have xcode 4.6 on os x lion which includes the ios sdk 6.1
go to xcode preferences to download and install the Command Line Tools so you have g++ etc.
Use cmake to compile opencv
go to the extracted opencv folder
create a build directory
mkdir build
cd build
cmake -D WITH_TBB=OFF -D BUILD_NEW_PYTHON_SUPPORT=OFF -D BUILD_FAT_JAVA_LIB=OFF -D BUILD_TBB=OFF -D BUILD_EXAMPLES=ON -D CMAKE_CXX_COMPILER=g++ CMAKE_CC_COMPILER=gcc -D CMAKE_OSX_ARCHITECTURES=x86_64 -D BUILD_opencv_java=OFF -G "Unix Makefiles" ..
make -j8
sudo make install
from the build folder, go to bin/ and run one of the tests
./opencv_test_stitching
Create your own c++ opencv xcode project
fire up xcode and create a new xcode project
select Command Line Tool for the type of project under os x
open your project's build settings
under Architectures, set Architecture to 64-bit intel. also set Valid Architectures to x86_64
under Build Options, set Compiler for C/C++ to Default Compiler
under Search Paths, set Header Search Paths to /usr/local/include
also under Search Paths, set Library Search Paths to /usr/local/lib
under Apple LLVM compiler 4.2 - Language set C++ Standard Library to libstd++ (For OpenCV 2.4.6, Xcode 5, LLVM 5.0, and 10.8.5, set both language dialect and std library to "Compiler Default" instead of "libstd++")
Add the compiled opencv libraries to your project
go the the Build Phases tab next to Build Settings tab you were in
inside Link Binary With Libraries, click on the + sign and choose Add Other
hit the front slash / on your keyboard and enter /usr/local/lib
hit enter and select the libraries you want to use in your project
make sure you always select libopencv_core.2.4.4.dylib
hit enter and you will see the selected dylibs under your project
write some code
first lets organize the files, right click on your project blueprint icon and select New Group
name the new group opencv or whatever
drag the dylibs and drop them in that group
open main.cpp
copy code from any of the sample tests that came with opencv and paste it here
make sure all the required dylibs are added, for example, if you copied the opencv_test_stitching.cpp code into main.cpp, you will need to add the following libraries in the previous steps
libopencv_core.2.4.4.dylib
libopencv_highgui.2.4.4.dylib
libopencv_stitching.2.4.4.dylib
Cheers.
It seems that your project is missing the framework AssetsLibrary.
Select the top node in the project navigator. (The project and targets page with the build settings appears.)
Select the target.
Select Summary.
Scroll down to Linked Frameworks and Libraries.
Click the Plus icon at the end of the table and select AssetsLibrary.framework.
Click Add.
Then try to build it again.
Since I can't seem to get an answer regarding the versions (neither here nor at the OpenCV Q&A site), I'm going to post this as an answer, as it at least solved the issue. This is described here.
In your project's Build Settings, go down to the section Apple LLVM compiler 4.1-Language.
There:
Set C++ Language Dialect to Compiler Default
Set C++ Standard Libray to libc++ (LLVM C++ standard libray with C++ 11 support
After doing the above, I stopped getting those linker errors, and only got one error instead, which stated that only iOS 5 and above is supported. Changing the Deployment Target to 5.0 in the project summery did the trick.
On a final note, I'm still not sure what it means, regarding OpenCV 2.4.3's compatibility with iOS versions older than 5.
clang: error: invalid deployment target for -stdlib=libc++ (requires iOS 5.0 or later) to remove this error.
GoTo BuildSettings. Set c++ standard library to compiler default. The
error will get removed surely.
Just to get this into the postings somewhere in case someone else runs into the same thing. If you follow all the great advice aboutsetting the proper c++ library to link against for building an iOS app BUT still get the link errors for undefined symbols make sure your code files are set to compile as c++! That is rename your .m to .mm and .h to .hpp. It's the little things...
Instead of using terminal commands given in the opencv installation guide in official website, use the following commands to build opencv from terminal. Worked for me.
cd OpenCV-2.3.1
mkdir build
cd build
cmake -G "Unix Makefiles" ..
make
sudo make install
Go Xcode/General/Linked Frameworks and Libraries
Press "+" button
type: AssetsLibrary
Select "AssetsLibrary.framework" and import it
Done
Good luck!