[libunwind] Is this possible with libunwind?

[Chris Markle]

David,

Could one use libunwind to accomplish the following, and if so, can you 
offer a hint or two as to which calls would be involved?

The idea here is to:

1) catch SIGSEGV in a signal handler (that part is easy).

2) print or emit in some way a stack trace. Best if it could be a stack 
trace as if the signal handler wasn't in the picture - the same kind of 
trace you'd get from gdb of an application that hadn't caught SIGSEGV.

3) somehow "unwind" (or whatever) so that the application runs as if the 
signal had not been caught. That is, return to the application at point 
of the SIGSEGV and let it core as if the signal had not been caught.

The intent here is to generate as close as possible of a core, including 
a "clean" backtrace, even while catching the SIGSEGV so as to be able to 
emit some backtrace info.

Thanks in advance for your response.

Chris Markle
VP, Engineering
Sendmail, Inc.