How does one compile 64-bit executables on HP-UX PA-RISC?

[Jeff Law]

  On 07/30/10 06:07, Dr. David Kirkby wrote:
> I have an HP C3600 workstation
>
> http://www.b2net.co.uk/hp/hp_visualize_c3600_workstation.htm
>
> which is fitted with 552 MHz PA-8600 PA-RISC CPU (64-bit) and 8 GB RAM.
>
> If I use gcc -m64, I get an error.
>
> drkirkby@hpbox:~$ gcc -m64 test.c
> cc1: error: unrecognized command line option "-m64"
>
> Can anyone tell me how to build 64-bit binaries with gcc on this machine?
GCC for the PA isn't runtime switchable between 32 and 64 bit binaries.  
ie, however GCC was initially configured is the only way it'll generate 
code on the PA.

What does gcc -v report?

Jeff