How do I decode error G_IO_QUARK from g_dbus_connection_call_sync()?

[jaklug (John Klug)]

This is g_dbus_connection_call_sync GError return.

I see this in DBUS-Monitor:

error time=1662507400.884091 sender=:1.128 -> destination=:1.813 error_name=org.bluez.Error.DoesNotExist reply_serial=28
   string "Does Not Exist"

When I try to decode it, I get:

domain 179 0xb3: code 36 0x24

g_quark_to_string(error->domain) gives me:

Domain: g-io-error-quark

What is the correct way to decode this error?

[andyholmes]

Not sure entirely what you want to decode, but you probably want to see Gio.DBusError which has some related functions and maybe Error Reporting.

Edit: Oh I missed that this was bluez, in which case device-api.txt may be useful.

[jaklug (John Klug)]

What I meant is a header file.

Looking in adapter-api.txt, it is missing:

DoesNotExist

But I see in BlueZ src/error.c:

DBusMessage *btd_error_does_not_exist(DBusMessage *msg)
{
return g_dbus_create_error(msg, ERROR_INTERFACE “.DoesNotExist”,
“Does Not Exist”);
}

So does this mean they only create a text message? I didn’t really want to have to scan a text message. I was hoping for a domain and code value.

[andyholmes]

Well I think D-Bus has it’s own error thing; GIO just has some utility functions for working with them. A GError looks like this:

struct GError {
  GQuark       domain;
  gint         code;
  gchar       *message;
};

So you can get the attributes of it with error->domain, error->code and error->message. Typically you will check against known errors like:

if (g_error_matches (error, G_DBUS_ERROR, G_DBUS_ERROR_FAILED)
  // etc

G_DBUS_ERROR_FAILED and G_IO_ERROR_FAILED are codes you get when there isn’t a more appropriate code like G_DBUS_ERROR_UNKNOWN_OBJECT, which may be the error code in your case.

DoesNotExist is on line #120 of device-api.txt, incidentally.

[jaklug (John Klug)]

Here is what seems to work:

g_error_matches(error,G_IO_ERROR,G_IO_ERROR_DBUS_ERROR)

That matches the code, and is a general error.

To get the bluez error you must do:

g_dbus_error_get_remote_error(error);

This will contain something like:

"org.bluez.Error.DoesNotExist"
or
"org.bluez.Error.AlreadyExists"

Thanks for the help.