gdb: The Ctrl-C Message
E.13.5 The 'Ctrl-C' Message
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If the 'Ctrl-C' flag is set in the GDB reply packet (
The F Reply
Packet), the target should behave as if it had gotten a break message.
The meaning for the target is "system call interrupted by 'SIGINT'".
Consequentially, the target should actually stop (as with a break
message) and return to GDB with a 'T02' packet.
It's important for the target to know in which state the system call
was interrupted. There are two possible cases:
* The system call hasn't been performed on the host yet.
* The system call on the host has been finished.
These two states can be distinguished by the target by the value of
the returned 'errno'. If it's the protocol representation of 'EINTR',
the system call hasn't been performed. This is equivalent to the
'EINTR' handling on POSIX systems. In any other case, the target may
presume that the system call has been finished -- successfully or not --
and should behave as if the break message arrived right after the system
call.
GDB must behave reliably. If the system call has not been called
yet, GDB may send the 'F' reply immediately, setting 'EINTR' as 'errno'
in the packet. If the system call on the host has been finished before
the user requests a break, the full action must be finished by GDB.
This requires sending 'M' or 'X' packets as necessary. The 'F' packet
may only be sent when either nothing has happened or the full action has
been completed.
Info Catalog
gdb: The F Reply Packet
gdb: File-I/O Remote Protocol Extension
gdb: Console I/O