如何判断一个静态库（.a文件）所支持的架构（平台）

问：

How
do I determine the target architecture of static library (.a) on Mac OS X?

I'm interested in verifying if a given iPhone static library has been built for ARM or Intel.

Its more curiosity than anything. Is there some kind of Mac OS X or BSD specific tool to do this? Thispost gives
an example in Linux.

方法1：

file

will
probably tell you.

otool

certainly
should be able to. But I'd try

file

first,
e.g.

logan:/Users/logan% file d2
d2: Mach-O executable ppc

Example with archive:

logan:/Users/logan% file /usr/lib/libMallocDebug.a
/usr/lib/libMallocDebug.a: Mach-O universal binary with 2 architectures
/usr/lib/libMallocDebug.a (for architecture i386):      current ar archive random library
/usr/lib/libMallocDebug.a (for architecture ppc):       current ar archive

方法2：

Another option is

lipo

,
it's output is brief and more readable that

otool

's.

Example:

% lipo -info /usr/lib/libiodbc.a
Architectures in the fat file: /usr/lib/libiodbc.a are: x86_64 i386 ppc
% lipo -info libnonfatarchive.a
input file libnonfatarchive.a is not a fat file
Non-fat file: libnonfatarchive.a is architecture: i386
%

方法3：

As mentioned earlier,

file

does
not always work.

otool
-hv

is probably the closest thing that is guaranteed to work - it gives architecture information for every single object file in the library.

Example:

% otool -hv /sw/lib/libfftw3.a
Archive : /sw/lib/libfftw3.a
/sw/lib/libfftw3.a(align.o):
Mach header
magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
MH_MAGIC_64  X86_64        ALL  0x00      OBJECT     3        336 SUBSECTIONS_VIA_SYMBOLS
/sw/lib/libfftw3.a(alloc.o):
Mach header
magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
MH_MAGIC_64  X86_64        ALL  0x00      OBJECT     3        416 SUBSECTIONS_VIA_SYMBOLS