20.4 Remote Configuration
This section documents the configuration options available when
debugging remote programs. For the options related to the File I/O
extensions of the remote protocol, see system-call-allowed.
set remoteaddresssize bits
- Set the maximum size of address in a memory packet to the specified
number of bits. gdb will mask off the address bits above
that number, when it passes addresses to the remote target. The
default value is the number of bits in the target's address.
- Show the current value of remote address size in bits.
set serial baud n
- Set the baud rate for the remote serial I/O to n baud. The
value is used to set the speed of the serial port used for debugging
show serial baud
- Show the current speed of the remote connection.
- If set to on, gdb sends a
BREAK signal to the remote
when you type Ctrl-c to interrupt the program running
on the remote. If set to off, gdb sends the ‘Ctrl-C’
character instead. The default is off, since most remote systems
expect to see ‘Ctrl-C’ as the interrupt signal.
- Show whether gdb sends
BREAK or ‘Ctrl-C’ to
interrupt the remote program.
set remoteflow on
set remoteflow off
- Enable or disable hardware flow control (
on the serial port used to communicate to the remote target.
- Show the current setting of hardware flow control.
set remotelogbase base
- Set the base (a.k.a. radix) of logging serial protocol
communications to base. Supported values of base are:
hex. The default is
- Show the current setting of the radix for logging remote serial
set remotelogfile file
- Record remote serial communications on the named file. The
default is not to record at all.
- Show the current setting of the file name on which to record the
set remotetimeout num
- Set the timeout limit to wait for the remote target to respond to
num seconds. The default is 2 seconds.
- Show the current number of seconds to wait for the remote target
set remote hardware-watchpoint-limit limit
set remote hardware-breakpoint-limit limit
- Restrict gdb to using limit remote hardware breakpoint or
watchpoints. A limit of -1, the default, is treated as unlimited.
set remote hardware-watchpoint-length-limit limit
- Restrict gdb to using limit bytes for the maximum length of
a remote hardware watchpoint. A limit of -1, the default, is treated
show remote hardware-watchpoint-length-limit
- Show the current limit (in bytes) of the maximum length of
a remote hardware watchpoint.
set remote exec-file filename
show remote exec-file
- Select the file used for
extended-remote. This should be set to a filename valid on the
target system. If it is not set, the target will use a default
filename (e.g. the last program run).
set remote interrupt-sequence
- Allow the user to select one of ‘Ctrl-C’, a
‘BREAK-g’ as the
sequence to the remote target in order to interrupt the execution.
‘Ctrl-C’ is a default. Some system prefers
is high level of serial line for some certain time.
Linux kernel prefers ‘BREAK-g’, a.k.a Magic SysRq g.
BREAK signal followed by character
- Show which of ‘Ctrl-C’,
is sent by gdb to interrupt the remote program.
BREAK-g is BREAK signal followed by
also known as Magic SysRq g.
set remote interrupt-on-connect
- Specify whether interrupt-sequence is sent to remote target when
gdb connects to it. This is mostly needed when you debug
Linux kernel. Linux kernel expects
BREAK followed by
which is known as Magic SysRq g in order to connect gdb.
- Show whether interrupt-sequence is sent
to remote target when gdb connects to it.
set tcp auto-retry on
- Enable auto-retry for remote TCP connections. This is useful if the remote
debugging agent is launched in parallel with gdb; there is a race
condition because the agent may not become ready to accept the connection
before gdb attempts to connect. When auto-retry is
enabled, if the initial attempt to connect fails, gdb reattempts
to establish the connection using the timeout specified by
set tcp connect-timeout.
set tcp auto-retry off
- Do not auto-retry failed TCP connections.
show tcp auto-retry
- Show the current auto-retry setting.
set tcp connect-timeout seconds
set tcp connect-timeout unlimited
- Set the timeout for establishing a TCP connection to the remote target to
seconds. The timeout affects both polling to retry failed connections
set tcp auto-retry on) and waiting for connections
that are merely slow to complete, and represents an approximate cumulative
value. If seconds is
unlimited, there is no timeout and
gdb will keep attempting to establish a connection forever,
unless interrupted with Ctrl-c. The default is 15 seconds.
show tcp connect-timeout
- Show the current connection timeout setting.
The gdb remote protocol autodetects the packets supported by
your debugging stub. If you need to override the autodetection, you
can use these commands to enable or disable individual packets. Each
packet can be set to ‘on’ (the remote target supports this
packet), ‘off’ (the remote target does not support this packet),
or ‘auto’ (detect remote target support for this packet). They
all default to ‘auto’. For more information about each packet,
see Remote Protocol.
During normal use, you should not have to use any of these commands.
If you do, that may be a bug in your remote debugging stub, or a bug
in gdb. You may want to report the problem to the
For each packet name, the command to enable or disable the
set remote name
-packet. The available settings
|Detecting multiple threads
|Stepping or resuming multiple threads
|Display MS-Windows Thread Information Block.
|Remote communications parameters
|Querying remote process attach state.
|Install tracepoint in tracing
Z0 and Z1
Support for target-side breakpoint condition evaluation