Error:Apple Mach-O Linker (Id) Warning

问题

In my app I have been working to import and export the database.

I have imported some files which is required for this functionality but when i try to run the app in simulator the errors listed below occurs. I can't understand which type of errors are these. so plz help me solve this problem.

Undefined symbols for architecture i386:
  "_inflateInit2_", referenced from:
      -[NSData(NSDataExtension) gzipInflate] in NSData+CocoaDevUsersAdditions.o
  "_inflate", referenced from:
      -[NSData(NSDataExtension) gzipInflate] in NSData+CocoaDevUsersAdditions.o
  "_inflateEnd", referenced from:
      -[NSData(NSDataExtension) gzipInflate] in NSData+CocoaDevUsersAdditions.o
  "_deflateInit2_", referenced from:
      -[NSData(NSDataExtension) gzipDeflate] in NSData+CocoaDevUsersAdditions.o
  "_deflate", referenced from:
      -[NSData(NSDataExtension) gzipDeflate] in NSData+CocoaDevUsersAdditions.o
  "_deflateEnd", referenced from:
      -[NSData(NSDataExtension) gzipDeflate] in NSData+CocoaDevUsersAdditions.o
ld: symbol(s) not found for architecture i386
collect2: ld returned 1 exit status

回答1:

You didn't include the libz.tbd where those functions are. Select the project node, select your target, go to the Build Phases tab, expand "Link Binaries With Libraries", add libz.dylib, and try again.

回答2:

Add libz.dylib to your framework, it will work..

回答3:

I faced the same issue, and thanks to Jano, it was resolved after I added the Libz.dylib to the project.

来源：https://stackoverflow.com/questions/7752127/errorapple-mach-o-linker-id-warning