Programming Utilities Guide

Reserved Words

Table 1-4 lists the reserved words. Enclose them in single quotes if you use them to select attributes or values.

Table 1-4 Reserved Words


`add`	`alloc`	`buffer`
`clear`	`connect`	`continue`
`create`	`dealloc`	`delete`
`disable`	`enable`	`fcns`
`filter`	`help`	`history`
`kill`	`ktrace`	`list`
`off`	`on`	`pfilter`
`probes`	`quit`	`resume`
`sets`	`source`	`suspend`
`trace`	`untrace`	`values`

For example:

enable 'trace'='on'

means enable all probes whose trace attribute has the value of ON. Both trace and on are reserved words, so they both have to be enclosed in single quotation marks.

Table 1-5 prex Commands


Command	Action
`clear $set_name` `clear` `selector_list`	Disconnect connected probe functions.
`clear $set_name` `clear` `selector_list`	Disconnect connected probe functions.
`connect &debug $set_name` `connect &debug` `selector_list`	Connect the debug function to the probe points. This does not enable the probe points. The debug function sends its output to `stderr` and not to the trace file.

`continue`	Resume execution of your program, leaving `prex` attached.
`create` `$set_name` `selector_list`	Create a set with probe points matching `selector_list`. Also creates an alias, $`set_name`, for the `selector_list`.
`enable $set_name` `enable` `selector_list` `disable $set_name` `disable` `selector_list`	Control whether the probe points perform the action they are set up for. Probe points are disabled by default; `prex` does not turn on tracing. The cheapest way (in terms of execution time at the probe point) to stop a probe point from tracing is to use the `disable` command. The `enable` and `disable` commands are a master switch. If a probe point is not enabled, even if the probe point is connected to the `debug()` function and `trace` is on, no information is sent to `stderr` or to the trace file.



`help`	List all available `prex` commands.
`list` `attribute`s `probes` `selector_list` `list` `attribute`s `probes $set_name`	List whether specified probe points are enabled or disabled, whether they have tracing on or off, and what the connected probe function is. Attributes are selectors as described in "Attributes ". For example, list name file probes $all lists only `name` and `file` values for matching probe points, while the command `list probes $all` lists all default attributes and their values (`name`, `enable`, `trace`, `file`, `line`, and `funcs`).

`list fcns`	List the defined functions (currently, only `&debug` is defined).
`list history`	List the control command history. The history of the commands used with `connect`, `clear`, `trace`, `untrace`, `enable`, and `disable` are executed whenever a new shared object is brought into your program through `dlopen()`. See "`dlopen()` and `dlclose()` and History".
`list sets`	List the defined sets.
`list values` `attributes`	List the unique values associated with the specified attributes. For example, `list values keys` lists all the unique keys in the program.
`source` `filename`	Source a file of `prex` commands. `filename` is a quoted string.
`trace $set_name` >`trace` `selector_list` `untrace $set_name` `untrace` `selector_list`	Control the tracing action of the probe points. `trace` and `untrace` determine whether a probe point generates a trace record when it is executed. Neither `trace` nor `untrace` enables the probe points. The default mode is that tracing is on. The `untrace` command is useful when you are interested in getting only debug output. If you are using this, your probe should be enabled with tracing off and debug on. Tracing disturbs your program less than the debug function does because `trace` writes to an `mmap`'d file while `debug` writes to `stderr`.



`quit`	Quit `prex`; if your program was loaded with `prex`, it will be killed; if your program was attached to `prex`, it will be resumed.
`quit kill`	Quit `prex` and kill your program.
`quit resume`	Quit `prex` and resume execution of your program.
`quit suspend`	Quit `prex` and leave your program suspended.