RTEMS GNU Tools On-Line Library

GDB/MI Output Syntax

Debugging with GDB

19.1.2: GDB/MI Output Syntax

The output from GDB/MI consists of zero or more out-of-band records followed, optionally, by a single result record. This result record is for the most recent command. The sequence of output records is terminated by `(gdb)'.

If an input command was prefixed with a token then the corresponding output for that command will also be prefixed by that same token.

output ==>: ( out-of-band-record )* [ result-record ] "(gdb)" nl
result-record ==>: [ token ] "^" result-class ( "," result )* nl
out-of-band-record ==>: async-record | stream-record
async-record ==>: exec-async-output | status-async-output | notify-async-output
exec-async-output ==>: [ token ] "*" async-output
status-async-output ==>: [ token ] "+" async-output
notify-async-output ==>: [ token ] "=" async-output
async-output ==>: async-class ( "," result )* nl
result-class ==>: "done" | "running" | "connected" | "error" | "exit"
async-class ==>: "stopped" | others (where others will be added depending on the needs---this is still in development).
result ==>: [ string "=" ] value
value ==>: const | "{" result ( "," result )* "}"
const ==>: c-string
stream-record ==>: console-stream-output | target-stream-output | log-stream-output
console-stream-output ==>: "~" c-string
target-stream-output ==>: "@" c-string
log-stream-output ==>: "&" c-string
nl ==>: CR | CR-LF
token ==>: any sequence of digits.

In addition, the following are still being developed:

query: This action is currently undefined.

Notes:

All output sequences end in a single line containing a period.
The token is from the corresponding request. If an execution command is interrupted by the `-exec-interrupt' command, the token associated with the `*stopped' message is the one of the original execution command, not the one of the interrupt-command.
status-async-output contains on-going status information about the progress of a slow operation. It can be discarded. All status output is prefixed by `+'.
exec-async-output contains asynchronous state change on the target (stopped, started, disappeared). All async output is prefixed by `*'.
notify-async-output contains supplementary information that the client should handle (e.g., a new breakpoint information). All notify output is prefixed by `='.
console-stream-output is output that should be displayed as is in the console. It is the textual response to a CLI command. All the console output is prefixed by `~'.
target-stream-output is the output produced by the target program. All the target output is prefixed by `@'.
log-stream-output is output text coming from GDB's internals, for instance messages that should be displayed as part of an error log. All the log output is prefixed by `&'.

See GDB/MI Stream Records, for more details about the various output records.

See GDB/MI Draft Changes to Output Syntax, for proposed revisions to the current output syntax.

Debugging with GDB