D.7 Interrupts

When a program on the remote target is running, No value for GDBN may attempt to interrupt it by sending a ‘Ctrl-C’ or a BREAK, control of which is specified via No value for GDBN's ‘remotebreak’ setting (see set remotebreak).

The precise meaning of BREAK is defined by the transport mechanism and may, in fact, be undefined. No value for GDBN does not currently define a BREAK mechanism for any of the network interfaces.

‘Ctrl-C’, on the other hand, is defined and implemented for all transport mechanisms. It is represented by sending the single byte 0x03 without any of the usual packet overhead described in the Overview section (see section Overview). When a 0x03 byte is transmitted as part of a packet, it is considered to be packet data and does not represent an interrupt. E.g., an ‘X’ packet (see X packet), used for binary downloads, may include an unescaped 0x03 as part of its packet.

Stubs are not required to recognize these interrupt mechanisms and the precise meaning associated with receipt of the interrupt is implementation defined. If the stub is successful at interrupting the running program, it is expected that it will send one of the Stop Reply Packets (see section Stop Reply Packets) to No value for GDBN as a result of successfully stopping the program. Interrupts received while the program is stopped will be discarded.