How to see the compilation platform of a static library file

Question

I had a static library file. How can I see whether it is compiled in i386 or in arm platform. Thanks.

See my answer then - unbeknownst to many (though you, as a programmer, probably do know) Mac OS X is a fullblown Unix system :) — Tim Čas, Feb 13 '12 at 13:05

score 18 · Answer 1 · edited Feb 13 '12 at 13:34

18

objdump is your friend ;)

$ objdump -f lib/lib.a

edited Feb 13 '12 at 13:34

oHo

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answered Feb 13 '12 at 13:05

yves Baumes

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Thanks :-D just simply than copying file, then archiving it, and finally using `file`. – oHo Feb 13 '12 at 13:35
objdump is better because the output of file can be a bit limited. – robert Oct 30 '14 at 17:00

Tim Čas · Accepted Answer · 2012-02-13T13:10:34.263

In Unix (and similar - say, Linux or Minix) systems, you can use the "file" utility:

%file /lib/libc.so.7
libc.so.7: ELF 64-bit LSB shared object, x86-64, version 1 (FreeBSD), dynamically linked, stripped

(the % indicates a shell prompt and is not part of the command)

As for Windows, I don't know if there is a built-in command already present, but if not, you can find the utility on this page: http://gnuwin32.sourceforge.net/packages.html (the file package is about 1/3 down the page).

EDIT: For static libraries (.a files), you first need to extract them and check a .o file:

%cp /usr/lib/libchipmunk.a .
%ar -x libchipmunk.a
%file *.o
chipmunk.c.o: ELF 64-bit LSB relocatable, x86-64, version 1 (FreeBSD), not stripped
<snip>

WARNING: ar -x ... will pollute the local directory, so be sure to copy the files somewhere else (say /tmp/something) first!

I'm sure there is a way to directly check into these files, but this works just as well!

file command does not give that much information for a static library (.a files). — yves Baumes, Feb 13 '12 at 13:09

score 1 · Answer 3 · answered Feb 13 '12 at 13:05

1

Use file or objdump. file always works but objdump will give you more detailed information about libraries and archives and executables.

answered Feb 13 '12 at 13:05

Aaron Digulla

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score 0 · Answer 4 · answered Jan 19 '22 at 15:52

For libraries linked to iOS apps, here's how to see the architectures of a .a file:

file /path/to/library.a

Example output for a lib built for armv7, armv7s (iPhone 5), arm64, x86_64, and i386:

/path/to/library.a: Mach-O universal binary with 5 architectures: [i386:Mach-O object i386] [x86_64:Mach-O 64-bit object x86_64] [arm_v7:Mach-O object arm_v7] [arm_v7s:Mach-O object arm_v7s] [arm64]
/path/to/library.a (for architecture i386):    Mach-O object i386
/path/to/library.a (for architecture x86_64):  Mach-O 64-bit object x86_64
/path/to/library.a (for architecture armv7):   Mach-O object arm_v7
/path/to/library.a (for architecture armv7s):  Mach-O object arm_v7s
/path/to/library.a (for architecture arm64):   Mach-O 64-bit object arm64

score 0 · Answer 5 · answered Feb 13 '12 at 13:04

0

file gives you general information about the platform on linux.

e.g.

file /usr/lib/libfoo.a

or for a executable binary

file `which foo`

answered Feb 13 '12 at 13:04

Zulan

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How to see the compilation platform of a static library file

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