I'm in no way a GDB expert. I believe it's currently using basic dwarf debugging information, basically just looking for the __sigtramp_siginfo_2 function name. If it finds that, it declares the sigtramp found. I do not believe it's using the cfi notations which are relatively recent if I understand correctly. What this discussion has gotten me wondering regarding gdb is if looking for __sigtramp_siginfo_2 is still a valid method of detection on the newer NetBSD releases.
The only reason I brought gdb up is because it's the other major user of KERN_PROC_SIGTRAMP sysctl so I thought NetBSD might benefit there too. John
