Re: About libdir for 64-bit

[Ralf Corsepius]

On 07/17/2013 10:11 PM, Russ Allbery wrote:
> Thomas Jahns <address@hidden> writes:
>
> > I couldn't propose anything. Is there even a method to reliably infer
> > the ABI from the compiler?
>
> Probing sizeof(long) with the configure compiler does a fairly good job
> for the most common cases,
Only on some common Linux distros.

In most other cases, guessing on multilib subdirs from sizeof(long) is 
not possible.

> which is why that's what the macro I posted
> does.  In particular, it works for the common cases of -m32 and -m64 on
> hosts with both library paths.
Right, but it suffers from the same limitations as Sergei's approach.

If you'd want to have a better guess, you have to apply some magic 
examining the multilib subdir involving compiler internals, e.g.
gcc --print-multi-os


Fedora x86_64/i386:
# gcc --print-multi-os -m64
../lib64

# gcc --print-multi-os -m32
../lib

RTEMS sparc64 (A 64 bit long) target:
# sparc64-rtems4.11-gcc --print-multi-os
.

RTEMS sparc64 (64 bit w/softfloat):
# sparc64-rtems4.11-gcc --print-multi-os -msoft-float
soft

x86_64-w64-mingw32 -m64 (Windows 64bit):
# x86_64-w64-mingw32-gcc --print-multi-os -m64
../lib

x86_64-w64-mingw32 -m32 (Windows 32bit)
# x86_64-w64-mingw32-gcc --print-multi-os -m32
../lib32


Ralf