ultrix man page for trace

trace(5)							File Formats Manual							  trace(5)

Name
       trace - system call tracer device

Description
       The  file  is the system call trace device. It supports the following system calls: and The device supports 16 (configurable in as TR_USRS)
       simultaneous users. It uses an 8192-byte buffer for trace records.  The choice of which system calls to trace is done with the system call.
       The  call  is  used for efficient reading of the device.  The call uses an 8192-byte buffer and returns when the buffer is 60% full.  It is
       required that the user use a buffer the same size as the system buffer size defined in as TR_BUFSIZE.  All operations are  defined  in  the
       header file, The calls are:

       --------------------------------
       ioctl	      arg (pointer to)
       --------------------------------
       IOTR_GETOFF    int a
       IOTR_GETON     int a
       IOTR_GETALL    int a
       IOTR_GETPIDS   int a[10]
       IOTR_GETUIDS   int a[10]
       IOTR_GETSYSC   int a[10]
       IOTR_GETPGRP   int a[10]
       IOTR_SETOFF    int a
       IOTR_SETON     int a
       IOTR_SETALL    int a
       IOTR_SETPIDS   int a[10]
       IOTR_SETUIDS   int a[10]
       IOTR_SETSYSC   int a[10]
       IOTR_SETPGRP   int a[10]
       --------------------------------

Examples
       A prototype example (with missing parts):
       char cmd[BUFSIZ],buf[TR_BUFSIZ];
       int pgrp[10],i;
       fd = open("/dev/trace",0);      /* open the device */
       pgrp[0] = dofork(cmd);	       /* fork the command to trace */
       for (i=1;i<TR_PGRP;i++)	       /* dofork sleeps 2 seconds while */
	       pgrp[i] = 0;	       /* we set up to do the trace */
       i = ioctl(fd,IOTR_SETPGRP,pgrp);/* set up for the trace */
       /* select code goes here */
       read(fd,buf,sizeof(buf));

See Also
       trace(1), close(2), ioctl(2), open(2), read(2), select(2)

																	  trace(5)