Re: [PATCH] Add Windows support for backtrace_functions (MSVC only)

On 2/23/2026 4:07 PM, Álvaro Herrera wrote:
> On 2026-Feb-23, Bryan Green wrote:
>
>> I have implemented DuplicateHandle and closed the handle in the
>> appropriate places. I also reset backtrace_process to NULL if
>> SymInitialize() fails. Patch is attached.
>
> Hmm, should then backtrace_cleanup() cope with the case where it's NULL?
>
> Also, I wonder what happens if one "backtraceable" error occurs, and we
> fail to SymInitialize(), then another backtraceable error occurs.
> Should we do the DuplicateHandle()+SymInitialize() dance again, or
> should we just give up? The current implementation does the former, I
> think; but the latter is also easily achievable by setting
> backtrace_symbols_initialized to true and leaving backtrace_process as
> NULL; then this case can be detected specifically in set_backtrace() and
> treated as a case where we just return NULL before attempting anything
> else.
>
backtrace_cleanup() only cleans up on process exit-- so, it is almost a
style choice. If we are going to close the handle in cleanup we should
probably stay consistent and reset backtrace_process to null as well.

If SymInitialize() fails...I can not imagine it ever succeeding after
that. It is an expensive call...a process generating errors shouldn't
be burning time retrying a failing system call on every error.

I agree with not retrying. I'll put together another patch with those
changes.

--
Bryan Green
EDB: https://www.enterprisedb.com