xscope - X Window Protocol Viewer
] [ -h<server-host>
] [ -q
] [ -r
] [ -I
sits in-between an X11 client and an X11 server and prints the
contents of each request, reply, error, or event that is communicated between
can decode the core X11 protocol and several extensions,
including BIG-REQUESTS, LBX, MIT-SHM, NCD-WinCenterPro, RANDR, and RENDER.
This information can be useful in debugging and performance tuning of X11
servers and clients.
To operate, xscope
must know the host, port, and display to use to
connect to the X11 server. In addition, it must know the port on which it
should listen for X11 clients. Two cases are common:
- (1) The X11 server is on the same host as xscope.
- In this case, the input port for xscope should be selected as an
X11 server on a different display, and the client DISPLAY argument
adjusted to select xscope . For example, if the X11 server is on
port 6001, display 1, then xscope can use port 6002 as its input
port. The client can use display 1 for direct access to X11 or display 2
for access to xscope.
- (2) The X11 server is on a different host than xscope.
- In this case the same input and output ports can be used, and the host
component of the DISPLAY is used to select xscope or X11.
- Specify the port that xscope will use to take requests from clients
(defaults to 1). For X11, this port is automatically biased by 6000.
- Determines the port that xscope will use to connect to X11
(defaults to 0). For X11, this port is automatically biased by 6000.
- Determines the host that xscope will use to find its X11
- Defines the display number. The display number is added to the input and
output port to give the actual ports which are used by xscope.
- Instead of decoding a live session, reads previously captured raw data
from a file to decode.
- Quiet output mode. Gives only the names of requests, replies, errors, and
events, but does not indicate contents.
- Determines the level of printing which xscope will provide. The
print-level can be 0 (same as quiet mode), 1, 2, 3, 4. The larger numbers
give more and more output. For example, a successful setup returns a
string which is the name of the vendor of the X11 server. At level 1, the
explicit field giving the length of the string is suppressed since it can
be inferred from the string. At level 2 and above the length is explicitly
- Print only raw data without decoding it.
- Print debugging information at the specified level.
- Enter interactive mode at startup.
- Toggle output on or off when SIGUSR1 is received. If n is 0, the
initial state is off. If n is 1, the initial state is on.
- Print version information and exit.
- Terminate xscope when all clients close.
receives an interrupt signal (normally generated by
Control-C) or is started with the -I flag, it enters an interactive mode in
which it prompts for commands. Available commands in this mode are:
- audio, a
- Show current verbosity level for NAS protocol packets.
- audio n, a n
- Set current verbosity level for NAS protocol packets to n.
- break, b
- List currently defined breakpoints.
- break request..., b request...
- Create a breakpoint for the specified protocol requests. The breakpoint
will be enabled by default. When the breakpoint is enabled, xscope
will stop for interactive commands after processing a request of the
specified type. Requests and extensions may be specified by name or
number. If an extension is followed by a ":" and a number, it
will only break for the specified minor opcode for that extension. Note
that since extension opcodes are not known until the extension is first
seen, breakpoints cannot currently be set on extensions until after a
QueryExtension request and reply are processed for that extension, so
users may need to initially set a breakpoint on QueryExtension, and after
processing that set the breakpoint for the target extension.
- cont, c
- Resume processing of data passing between server and clients.
- delete, del
- Delete all breakpoints.
- delete breakpoint..., del breakpoint...
- Delete listed breakpoints, specified by number.
- disable, d
- Disable all breakpoints.
- disable breakpoint..., d breakpoint...
- Disable listed breakpoints, specified by number.
- enable, e
- Enable all breakpoints.
- enable breakpoint..., e breakpoint...
- Enable listed breakpoints, specified by number.
- help, ?
- Print list of available commands.
- help command..., ? command...
- Describe specified command or commands.
- level, l
- Show current verbosity level for X11 protocol packets.
- level n, l n
- Set current verbosity level for X11 protocol packets to n.
- quit, q
- Quit xscope.
- step, s
- Process one request, then prompt for another command.
xscope -v4 -hcleo -d0 -o0 -i1
This command would have xscope communicate with an X11 server on host ``cleo'',
display 0; xscope itself would be available on the current host as display 1
(display of 0 plus the 1 of -i1). Verbose level 4.
xscope -q -d1 -o1 -o3
The X11 server for the current host, display 2 (1 for -d1 plus 1 for -o1) would
be used by xscope which would run as display 4 (1 for -d1 plus 3 for -o3).
Quiet mode (verbose level 0).
(7), X11 Protocol and extension protocol documents
James L. Peterson (MCC)
Copyright (C) 1988 MCC
Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright
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the name of MCC not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior permission. MCC
makes no representations about the suitability of this software for any
purpose. It is provided "as is" without express or implied warranty.
MCC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED
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