strace - Writes STREAMS event trace messages to standard output
/usr/sbin/strace [mod_ID sub_ID pri_level]
The strace command gets STREAMS event trace messages from STREAMS drivers and modules via the STREAMS log driver (strlog), and writes these messages to standard output. You can limit the messages strace receives by specifying arguments to the command. The arguments, which must be specified together, are the following: Specifies the STREAMS module identification number. Specifies a subidentification number (often corresponding to a minor device). Specifies a tracing priority level. The strace command will get messages of a level equal to or less than the value in the pri_level argument. The value of the argument must be a nonnegative integer.
You can specify all as the value for any of the arguments in the strace command line. The value all indicates that there are no restrictions for that argument.
You can also specify multiple sets of the command's three arguments to obtain the messages from more than one driver or module.
More than one strace process can open the STREAMS log driver at a time. When you invoke strace, the log driver compares the sets of arguments from the command line with actual trace messages, returning the messages that satisfy the criteria.
STREAMS event trace messages have the following format: seqnum stdtime tickstime pri_level ntfycode mod_ID \ sub_ID msgtext where: The event trace sequence number. The time the message was sent, in the format hh:mm:ss. The time the message was sent, measured in machine ticks since the last boot. The tracing priority level as defined by the STREAMS driver or module that originates the messages. Can be either of the following indicators: Indicates that the message has also been saved in the error log. Indicates that the message signaled a fatal error. The module identification number of the trace message source. The subidentification number of the trace message source. The trace message text.
The strace command runs until terminated by the user.
Running strace with several sets of arguments can negatively affect STREAMS performance, particularly for those modules and drivers sending the messages.
Also be aware that strace may not be able to handle
a large number of messages. If drivers and modules return
messages to strace too quickly, some may be
To display all trace messages received from the driver or module identified by mod_ID 28, enter: strace 28 all all To display those trace messages from the driver or module identified by mod_ID 28 and its minor devices identified by the sub_IDs 2, 3, and 4, enter: strace 28 2 all 28 3 all 28 4 all
This command line causes messages of any tracing priority level
to be displayed.
To display the trace messages from the same driver or module and sub_IDs,
but limited to certain priority levels, enter:
strace 28 2 0 28 3 0 28 4 1
This command line specifies that messages from driver or module
28 and sub_IDs 2 and 3
must have a tracing priority of 0, and those from sub_ID
4 must have a tracing priority equal to or less than 1.
Commands: strclean(8), strerr(8).
Interfaces: strlog(7). delim off