warning: garbage in qC reply

Hi,

I'm writing a new GDB stub in Python, and while implementing
each command that is sent to me by the GDB client during
the attach phase, I'm facing an issue with the qC command:

GDB is asking me to set the current thread-id to -1, with Hc-1
and immediately after it query the current thread id, with qC
I return -1 with QC-1, and I get a warning:

Sending packet: $Hc-1#09...Ack
Packet received: OK
Sending packet: $qC#b4...Ack
Packet received: QC-1
warning: garbage in qC reply

Is -1 an invalid thread-id syntax for qC ?

Thanks !
--
Mathieu Tarral

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