Uncaught exception when throwing within with_libc lambda

[Sid Hussmann]

Dear Genodians,

I just stumbled across a not so obvious characteristic of the with_libc lambda. Not so obvious to me, at least.
If I run following code snipped, it will result in a "Error: Uncaught exception of type 'Genode::Exception'":


``` 
try {
	Libc::with_libc([&] () {
		throw Genode::Exception();
	});
} catch (...) {
	Genode::log("caught libc exception");
}
```

I didn't find any documentation regarding the with_libc lambda in combination with exceptions.
Is this expected behavior?
What would be the right pattern to forward the exception to a pure Genode environment e.g. across RPC boundaries?
I could think of following pattern:


``` 
bool libc_exception_thrown = false;
Libc::with_libc([&] () {
	try {
		throw Genode::Exception();
	} catch (...) {
		Genode::log("caught libc exception");
		libc_exception_thrown = true;
	}
});
if (libc_exception_thrown) {
	throw My_rpc_exception();
}
``` 

However, it does not look like the most elegant solution...

Cheers,
Sid


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