Envoy Configuration and Management Manual

Tr acing
Envoy Configuration and Management Manual—429861-001
6-5
FROM Command
For information on starting PTrace and entering PTrace commands, and for more
detailed descriptions of the PTrace commands available to all subsystems, refer to the
PTrace Reference Manual.
FROM Command
The FROM command causes the PTrace kernel to open the specified trace file and read
the device type and subtype information from the header. If a trace file is currently in
use, PTrace closes it before opening the new one.
The command syntax is as follows:
Considerations
When the FROM command is used, PTrace automatically invokes the STATETABLES
command. The subsystem associated with the trace file specified in the FROM
command determines which state-machine file name is used by the STATETABLES
command. The state-machine file name that PTrace looks for is
$SYSTEM.SYSnn.ZENVSMT. If this file cannot be accessed, no error message is
issued.
•
The FROM command resets current session parameters to their default values. For
more information about the resetting of current session parameters, see the RESET
command in the PTrace Reference Manual.
•
The FROM command resets current SELECT options to their default values if the
device type and subtype of the new trace file are different from the last trace file. If
the device type and subtype of the new trace file are the same as the last trace file,
SELECT options and state-table labels are not reset.
Table 6-2. PTrace Commands for Envoy
Command Description
FROM Command on page 6-5 Specifies the trace file to be displayed.
NEXT Command on page 6-6 Displays the next trace data record(s) in the
trace file.
RECORD Command on page 6-6 Displays the record(s) selected by record
number.
SELECT Command on page 6-7 Establishes selection criteria for displaying
trace records.
STATETABLES Command on page 6-9 Specifies the name of the file used for the
display of state-machine labels.
Note. The Envoy subsystem does not implement the FILTER or the TEST command. If you try
to specify the FILTER or the TEST command, PTrace responds with an error message.
FROM file-name