I have an sgi altix machine, it's itanium 2 architecture running Novell SLES 10, gcc 4 compiler.

I wrote some C++ code that has to link to 3rd party libraries which are only available for x86_64 linux and not specifically for ia64.

Is there a way to compile my C++ code and link such that it can use the libraries?
Right now when I try it the compilers says skipping incompatible .a file.

we have some other software that when we run it, we have a script first that does a setenv ARCH lnx86 before it executes the script and it works fine. So that gives me the impression at least there is a way to read x86_64 library files, which are *.a files, on an ia64 machine.

Hi -

Short answer: "Yes, you probably can".

Longer answer:
1. You're aware, of course, that x86 (32-bit) and Itanium (64-bit) are completely different architectures.

2. As such, the binaries (.o objects, .a libraries, .so shared libraries, executable programs, etc) have a signature in their header differentiating one from the other.

3. Most (not necessarily all, but more) 64-bit OS's have parallel 32-bit and 64-bit environments (i.e. every standard shared library has both a 64-bit veresion as well as a 32-bit equivalent).

The same goes for development packages: you'll usually have parallel 32- and 64-bit binaries.

4. You should be aware that I64 and Itanium are also completely different architectures.

5. Having said all that, you're going to have to sort out for yourself just what combinations your OS does and doesn't support.

I would start out by trying to build a "hello world", in both 32- and 64-bit versions, and see what happens.

These links might help:

http://en.wikipedia.org/wiki/X86-64#History_of_Intel_64

http://en.wikipedia.org/wiki/Itanium

Other platforms may have the ability to use the IA32 emulation capabilities of Itanium (both hardware and software emulation), but linux, AFAIK, does not support this (and never did). I do not believe support for the IA32 portion of the ABI is normative to implementors, and the linux people decided that mixed code was a bad idea at the beginning.

So my short answer is, “no, you probably can’t.”