MacOSX: find out if a process (given a PID) is running in 32bit or in 64bit Intel mode

I have a PID and I want to find out if the process is running in 32bit or in 64b开发者_StackOverflow社区it Intel mode. How?

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I can do via NSRunningApplication.

[[NSRunningApplication runningApplicationWithProcessIdentifier:pid] executableArchitecture]

returns the Mach-O architecture constant.

This works only for GUI applications, though...