STRACE(1M)          RISC/os Reference Manual           STRACE(1M)



NAME
     strace - print STREAMS trace messages

SYNOPSIS
     strace [ mid sid level ] ...

DESCRIPTION
     strace without arguments writes all STREAMS event trace mes-
     sages 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 tri-
     plets 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 may 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 will continue to execute until ter-
     minated by the user.

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

          strace  41 all all





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STRACE(1M)          RISC/os Reference Manual           STRACE(1M)



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

          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.

CAVEATS
     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 com-
     mand 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 tri-
     plets will have a greater impact on overall STREAMS perfor-
     mance.  Running strace will have the most impact on the tim-
     ing 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,
     then some of the messages will be lost.  This last case can
     be determined by examining the sequence numbers on the trace
     messages output.

SEE ALSO
     log(7).
     STREAMS Programmer's Guide.



























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