编译错误 ld: 41 duplicate symbols for architecture x86_64

Xcode输出这种错误

ld: 41 duplicate symbols for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

FinallyI find out the reason of this error cause I added -ObjC to the Other Linker Flags.

Reason：accepted41 duplicate symbols for architecture x86_64Means that you have loaded same functions twice. As the issue disappear after removing -ObjCfrom Other Linker Flags, this means that this option result that functions loads twice:

from Technical Q&AThis flag causes the linker to load every object file in the library that defines an Objective-C class or category. While this option will typically result in a larger executable (due to additional object code loaded into the application), it will allow the successful creation of effective Objective-C static libraries that contain categories on existing classes.