I've been trying to compile some C files to use in XCode that uses Openssl as a dependency for encryption. When compiling with clang the code compiles fine. I read a few posts on here like Setting C++ compile flags in xcode that says to put the flags under Other Linker Flags but I still couldn't get it to recognize it.
Here is the compiling command that works on the command line:
Flags in XCode:
The error in XCode:
Solution thanks to #WhozCraig
Add the include folder in "Header Search Paths" and library folder in "Library Search Paths"
Then put -lcrypto to link the files under "Other Link Flags"
I'm trying to build DLIB for an iOS project. Running the cmake results in a libdlib.a and a load of .o files.
When I add the library to an Xcode project I get warning that the library hasn't been built for arm64.
My question is two-part:
How can I build DLIB for iOS (I tried cmake **path_to_source** -DCMAKE_OSX_ARCHITECTURE="arm64" but it caused loads of errors e.g. unknown type name '__uint32_t'; did you mean '__uint128_t')?
What is the purpose of all the .o files that get built when you run cmake? Do I need to include them in an Xcode project?
I finally figured out how to do this:
Requirements
X11 (on a mac you can just open the X11 app and if X11 isn't installed it'll take you to the download).
Xcode
cmake (you can use home-brew for that)
Steps
In terminal make the lib-xx.xx/examples your root
Run:
mkdir build
cd build
cmake -G Xcode ..
cmake --build . --config Release
This will create a folder called dlib_build in which you can find an Xcode project that compiles the library. In the build settings of that Xcode project you can set the build architecture and SDK for any Xcode supported OS you like!
EDIT:
You have to include a lot of custom compiler flags and 3rd party libraries to get dlib to work in a project. Check out the examples.xcproject build settings.
To compliment RASS's answer, I am attaching screenshots showing how to change this to and from an iOS and OSX lib
After opening the project,
Select the project file from the project navigator
Select the dlib target all the way down the bottom
Select 'Build Settings'
Expand 'Base SDK' drop down
Select either iOS or macOS (OSX)
I hope this helps some people out! gl
Rob Sanders and mylogon already show how to build dlib for ios, here is how to use it:
add libdlib.a to project, and add path to library search paths
add all source to include directory(do not add to project), and add path to header search paths.
add accelerate framework, which contains blas symbols.
add preprocessor macros, from building settings, "custom compiler flag"/"other c flags". these macros make sure the header files match the lib.
-DDLIB_JPEG_SUPPORT
-DDLIB_NO_GUI_SUPPORT
-DNDEBUG
-DDLIB_USE_BLAS
-DDLIB_USE_LAPACK
I am using CocoaPods and have XCDYouTubeVideoPlayer as a pod. Recently I had to change my app to support 64-bit, so I upgraded XCDYoutubeVideoPlayer to the latest version using pod install. I also changed my project to use the Standard architectures setting.
After cleaning and trying to run on the device I get the following errors:
In Other Linker Flags I am using $(inherited).
Strangely, I can archive the project successfully without errors.
Any advice on how I can fix this?
I've been using XCDYouTubeVideoPlayer recently too and been cross-checking my project settings with regards to it.
Other Linker Flags:
$(inherited)
-l"Pods-XCDYouTubeKit"
Header Search Paths
$(inherited)
"${PODS_ROOT}/Headers/Public/XCDYouTubeKit"
Framework Search Paths
$(inherited)
All shown entries are for Debug and Release the same
Hope this will help you out.
I am integrating opencv2.framework with my project. I did the following steps for completion.
Added opencv2.framework to "Linked Frameworks and Libraries"
Added libc++.dylib to "Linked Frameworks and Libraries"
Added following code to AppName-Prefix.pch file
#ifdef __cplusplus
#import "opencv2/opencv.hpp"
#endif
Changed compiler default of
Apple LLVM compiler 4.2 - Language -> C++ Language Dialect -> GNU++11 [-std=gnu++11]
C++ Standard Library -> libc++ (LLVM C++ standard libray with C++ 11 support)
Still I am getting a link error which is saying
"opencv2.framework/opencv2(surf.o)
ld: 21 duplicate symbols for architecture armv7"
Can anyone help me on this?
EDIT:
My XCode version is 4.6, IOS SDK is 6.1 and deployment target is 4.3 (I tested with 5.0 also, but not working in that target too)
Update: github pull request which fixes this issue is now merged to OpenCV.
Cause:
In OpenCV source, there are two files named 1. surf.cpp and 2. surf.ocl.cpp which results in two surf.o object files for each architecture inside opencv framework library.
Fix:
In OpenCV source, apply patch from github pull request
and Build OpenCV for iOS.
See: Use lipo on OpenCV to extract separate libs for each architecture ( armv7, armv7s and i386 ) and then use ar -tv to see two object files of same size with name surf.o
I don't know: Only some XCode projects fails with the pre built OpenCV framework. I use Xcode 5.0 with OpenCV 2.4.6.1. Can this be fixed with some XCode build setting ?
My project was working just fine until this morning. I was using xcode 4.3, and an older version of OpenCV (I'm not sure about the exact version). OSX was already 10.7.x, but not 10.7.5
Today, after upgrading OSX to 10.7.5, xcode to 4.5.2, and downloading OpenCV 2.4.3, I am getting the following linker errors when trying to build the project:
Undefined symbols for architecture armv7:
"_OBJC_CLASS_$_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!