Undefined symbols for architecture arm64: “cv::String::deallocate()”

Question

When I add a ".a" file which includes opencv.framework,Xcode encountered such compile errors:

I am pretty sure opencv.framework is there,and I am using opencv 3.1,it should already support arm64. But why does it keep complaining about this? How can I fix it? Thanks a lot.

lipo - info shows following information: Architectures in the fat file: /Users/Fumin/libVisageWrapper.a are: armv7 i386 x86_64 arm64

Answer 1

You should verify that the library is correctly supporting arm64 using this command:

lipo -info libYourLib.a 

The output of this command should show this:

Architectures in the fat file: libYourLib.a are: armv7 arm64 

A fat file means a file which holds binary elements for possibly more than one architecture.

If arm64 is missing, you can't build a target for arm64 devices. You might need to ask your supplier of the library to build a fat version which includes the arm64 architecture.

Answer 2

It turns out there is already an opencv library in some other library,so two instance opencvs are conflictting with each other. After .a file provider provide a new version using the same opencv library, now it works fine.