How to check if a static library is built for 64-bit?

Solution 1:

Yes, an arm64 slice is there. To see it, you need to use lipo from the iOS toolchain, not from the host system (which doesn’t know about arm64):

xcrun -sdk iphoneos lipo -info $(FILENAME)

Solution 2:

good old file can do the trick, too:

$ file libTestFlight.a

libTestFlight.a: Mach-O universal binary with 5 architectures
libTestFlight.a (for architecture armv7):   current ar archive random library
libTestFlight.a (for architecture armv7s):  current ar archive random library
libTestFlight.a (for architecture i386):    current ar archive random library
libTestFlight.a (for architecture x86_64):  current ar archive random library
libTestFlight.a (for architecture cputype (16777228) cpusubtype (0)):   current ar archive random library

It seems that nobody at Apple cared to add the arm64 cputype to file, yet.

Interestingly, in the iOS 7 Tech Talk Videos ("Architecting Modern Apps, Part 2", PDF page 35) they show a working file tool's output:

Solution 3:

For a .framework

lipo -info myFramework.framework/MyFramework