Question

On AIX, I would run:

ar -X32 -t libdb2.a

and check for output to determine if there is a 32-bit object in the archive. Similarly with -X64 for checking for a 64-bit object. However, what about if I m on another platform, and need to check the archive to see what it has? Usually I m on Linux when I need to check, but I could just as easily be on Solaris or HP-UX.

I used to check for shr.o and shr_64.o, since that s what s being compiled, but those are starting to show up in actual messages that are in the archives, and thus the reliability of these have dropped to the point where I m getting false positives.

If anyone has a pointer, preferably something I can do in perl, that d be great.

Answer 1

I don t think there is an easy way. If you create two AIX archives, one 32-bit and one 64-bit, as follows:

$ cat a.c
int foo (void) { return 42; }
$ xlc -q32 a.c -c -o a32.o
$ xlc -q64 a.c -c -o a64.o
$ ar -X32 cr a32.a a32.o
$ ar -X64 cr a64.a a64.o

you end up with archives that are not in a readable format by the linux ar:

$ file a32.a a64.a 
a32.a: archive (big format)
a64.a: archive (big format)
$ ar t a32.a
ar: a32.a: File format not recognized
$ ar t a64.a
ar: a64.a: File format not recognized

I tried using strings to see if anything obvious was in the archives, but found nothing. Your ony remaining option is to build a binutils package targetting AIX (download binutils, configure with option --target=powerpc-ibm-aix5.3, run make and voilà: you ve got a tool called powerpc-ibm-aix5.3-ar somewhere in that build tree).

Answer 2

I d suggest extract one of the .o files from the .a archive, and then running the file command on it. Example:

$ file fortune/fortune.o
fortune/fortune.o: ELF 32-bit MSB relocatable, SPARC, version 1 (SYSV), not stripped

file isn t standard on every system, but can easily be compiled. Alternatively, there are a couple of perl modules which do the same thing as file.

ar offers the p command which prints the file in question. For example:

$ ar p libcurl.a base64.o > /tmp/base64.o
$ file /tmp/base64.o  
base64.o: ELF 32-bit LSB relocatable, Intel 80386, version 1 (SYSV), not stripped

Answer 3

So... I m one year late, but I just had the exact same problem. Here is how I solved it, I hope it helps someone:

$ ar t mylib.a
myobj1.o
myobj2.o
myobj3.o

$ mkdir /tmp/mylib
$ cp mylib.a /tmp/mylib
$ cd /tmp/mylib
$ ls
mylib.a

$ ar x mylib.a
$ ls
mylib.a
myobj1.o
myobj2.o
myobj3.o

$ file *

Possible outcomes:

mylib.a: current ar archive
myobj1.o: ELF 64-bit (...)
myobj2.o: ELF 64-bit (...)
myobj3.o: ELF 64-bit (...)

OR

mylib.a: current ar archive
myobj1.o: ELF 32-bit (...)
myobj2.o: ELF 32-bit (...)
myobj3.o: ELF 32-bit (...)

Explanation: An archive library file is just a collection of ".o" files, when you use the "t" argument of ar you list the contents of the archive and when you use the "x" argument of ar you extract them. Type man ar for further instructions.

友情链接