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Logging C++ exceptions inside try/catch block #1229
Description
Hello,
I'm trying to log an exception from a catch block in our C++ app with sentry native 0.6.6
Currenty the catch block is declared with
catch(...) {
/* set bad return code */
}According to docs/AI i've changed it to:
catch (std::exception& ex) {
GetApp()->LogException("std::exception", ex.what(), NULL);
/* set bad return code */
}and log the exceptions with:
void LogException(const char* szExceptionType, const char* szExceptionValue, const char* szEventMessage)
{
auto event = sentry_value_new_message_event(SENTRY_LEVEL_FATAL, nullptr, szEventMessage);
auto exception = sentry_value_new_exception(szExceptionType, szExceptionValue);
sentry_event_add_exception(event, exception);
sentry_value_set_stacktrace(exception, nullptr, 0);
const auto uuid = sentry_capture_event(event);
}Basically it's working, but I'm not sure if I'm collecting all types of exceptions?
for instance the following is not captured as std::execption and falls through the default catch (...) handler:
*((unsigned int*)0) = 0xDEAD01;
Activity
supervacuus commentedon May 8, 2025
In short: no.
catchwill only receive C++ exceptions, not allSEHexceptions. If you want to handleSEHexceptions, which includes hard faults like memory access errors and C++ exceptions, you need to use the SEH primitives.std::exception, thus guaranteeing awhat()interface. In C++, you can throw almost anything (besides incomplete or abstract types), so even if you only consider catching C++ exceptions, you will ignore all that aren't astd::exception.Yes, a
NULL-pointer dereference does not result in a C++ exception, and such acatchwill be bypassed. While C++ exceptions are implemented in terms ofSEHexceptions on Windows,SEHexceptions are a superset. If you want to handle allSEHexceptions, use theSEHprimitives (__try,__except,__finally). However, these are at a much lower level (you'd have to manually filter the incomingSEHexception to identify it as a C++ exception) and have different semantics. Of course, these handlers are not portable to other platforms.