Sun 64-bit problem

[Philip Cheng]

I installed gcc 3.1 on my Solaris 2.7.  Then I built a simple C program 
using gcc -m64 flag on the Solaris 2.7 machine.  The program runs successfully
on the Solaris 2.7 machine.

When I tried to run the program on my Solaris 2.8 machine, it came back with
an error.

Cannot execute binary file.
a.out: Exec format error

When I did not use -m64 flag, the program will run on my Solaris 2.8 machine.
Any ideas how to fix the problem?   Am I missing some flags?

Philip