Re: [boost] [Stacktrace] review, please stop discussing non-Stacktrace issues

On 12/18/16 20:15, Antony Polukhin wrote:

2016-12-18 0:29 GMT+03:00 Andrey Semashev :

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On Sat, Dec 17, 2016 at 9:17 PM, Niall Douglas wrote:

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Specifically:

1. Should Stacktrace be async safe so it can be used to print a stacktrace from a signal/exception handler?

That depends on whether any backend supports decoding the stacktrace in signal handlers. Note that if we also want to load debug symbols from a separate file while doing this, the task seems to become impossible.

Spawning a new subprocess in signal handler (or at the beginning of the program) would be OK for you? If I'll came up with an async_safe_print(stacktrace()); function that may fix the broken example in docs, provide much more motivation for having non allocating stacktrace class.

If that is only possible by forking a process then I'm not sure that accomplishes much. I mean, if there is a non-signal-safe formatting function for stacktraces, there's no problem to call `fork()` yourself in the signal handler, use that formatting function in the child process, and pipe its result back to the main process. I guess, a helper function that does this would be useful, just make sure to explicitly document that it forks. Also, the non-forking formatting implementation is still needed for all cases other than signal handlers.