strace(1M)							    strace(1M)

NAME    [Toc]    [Back]

     strace - print STREAMS trace messages

SYNOPSIS    [Toc]    [Back]

     strace [ mid sid level ] ...

DESCRIPTION    [Toc]    [Back]

     strace without arguments writes all STREAMS event trace messages from all
     drivers and modules to its	standard output.  These	messages are obtained
     from the STREAMS log driver (log(7)).  If arguments are provided they
     must be in	triplets of the	form mid, sid, level, where mid	is a STREAMS
     module ID number, sid is a	sub-ID number, and level is a tracing priority
     level.  Each triplet indicates that tracing messages are to be received
     from the given module/driver, sub-ID (usually indicating minor device),
     and priority level	equal to or less than the given	level.	The token all
     can be used for any member	to indicate no restriction for that attribute.

     The format	of each	trace message output is:

	  <seq>	<time> <ticks> <level> <flags> <mid> <sid> <text>


     <seq>     trace sequence number

     <time>    time of message in hh:mm:ss

     <ticks>   time of message in machine ticks	since boot

     <level>   tracing priority	level

     <flags>   E : message is also in the error	log
	       F : indicates a fatal error
	       N : mail	was sent to the	system administrator

     <mid>     module ID number	of source

     <sid>     sub-ID number of	source

     <text>    formatted text of the trace message

     Once initiated, strace continues to execute until terminated by the user.

EXAMPLES    [Toc]    [Back]

     Output all	trace messages from the	module or driver whose module ID is
     41:

	  strace  41 all all

     Output those trace	messages from driver/module ID 41 with sub-IDs 0, 1,
     or	2:





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strace(1M)							    strace(1M)



	  strace  41 0 1  41 1 1  41 2 0

     Messages from sub-IDs 0 and 1 must	have a tracing level less than or
     equal to 1.  Those	from sub-ID 2 must have	a tracing level	of 0.

SEE ALSO    [Toc]    [Back]

     log(7).

NOTES    [Toc]    [Back]

     Due to performance	considerations,	only one strace	process	is permitted
     to	open the STREAMS log driver at a time.	The log	driver has a list of
     the triplets specified in the command invocation, and compares each
     potential trace message against this list to decide if it should be
     formatted and sent	up to the strace process.  Hence, long lists of
     triplets have a greater impact on overall STREAMS performance.  Running
     strace has	the most impact	on the timing of the modules and drivers
     generating	the trace messages that	are sent to the	strace process.	 If
     trace messages are	generated faster than the strace process can handle
     them, some	of the messages	will be	lost.  This last case can be
     determined	by examining the sequence numbers on the trace messages
     output.


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