tuneinfo2(2)							  tuneinfo2(2)

NAME
       tuneinfo2() - retrieve detailed information about kernel tunable param‐
       eters

SYNOPSIS
DESCRIPTION
       This function provides detailed information about  one  or  all	kernel
       tunable	parameters.  If a particular parameter is of interest, specify
       it by name in tunable.  Otherwise, set tunable to NULL and  information
       will be returned on all kernel tunable parameters (if the supplied buf‐
       fer is big enough).

       version must always be set to

       Information about the selected tunable parameters is returned in struc‐
       tures and associated character strings.	The buf parameter must specify
       an address in the caller's space containing space for these  structures
       and strings.

       bufsize	must point to a variable containing the size of the buffer (in
       bytes).

       Since the character strings are of variable  length,  the  caller  must
       first  ask how much buffer space is needed, then allocate the necessary
       buffer space, and then ask for the tunable information.	 To  calculate
       the  size  of the buffer to hold all the tunables, this function should
       be called with the parameters buf and bufsize set  to  NULL  and	 zero,
       respectively.   The  function  will  return  successfully with a return
       value of 0 and the variable at bufsize will have been changed  to  con‐
       tain the amount of space needed to hold all of the requested data.  See
       the example below.

       Each structure describes a single tunable parameter,  and  contains  at
       least the following fields, in unspecified order:

       Location of the character string containing the name of the tunable.

       Location	 of  the character string containing an English description of
       the parameter.

       Location of the character string containing name of the DLKM module  in
       which the parameter is defined.
		 This  will  be	 a null string for those parameters defined in
		 the core kernel.

       The current value of the parameter.

       The boot-time value of the parameter.

       The HP-supplied default value of the parameter.

       The minimum value of the parameter.
		 Valid only if the flag is set in the word, below.

       The maximum value of the parameter.
		 Valid only if the flag is set in the word, below.

		 Note: The minimum and maximum values returned here are	 rela‐
		 tively	 static	 limits.  They will reflect the limitations of
		 the operating system software, and any limitations placed  on
		 this tunable parameter by the current values of other tunable
		 parameters.  However, they do not reflect any restrictions on
		 the tunable value based on transient factors like the current
		 usage pattern of the system.

		 For example, the maximum value returned for (the maximum num‐
		 ber of processes a non-root user may have) will be no greater
		 than the current value of (the maximum number of processes on
		 the system) minus 5.  However, the minimum value returned for
		 may very well be less than the number of processes that  some
		 user currently has.

       A bitmask of zero or more of the following flags:

		 The value of this parameter can be changed using

		 The value of this parameter can be changed using
				   without requiring a reboot.

		 The  values,  minima and maxima, for this parameter should be
		 interpreted
				   as signed quantities.

		 The		   field contains a minimum allowed value  for
				   this parameter.

		 The		   field  contains a maximum allowed value for
				   this parameter.

       The character string location fields, and can be used to	 retrieve  the
       character strings.  These fields must be accessed using the macro.  The
       first parameter of the macro is the pointer to the  structure  and  the
       second  parameter  is one of the four field names above.	 The result of
       the macro will be a pointer to a null-terminated string.	 See the exam‐
       ple below.

RETURN VALUE
       If is successful, it returns the number of tunable parameters for which
       information was returned and sets the value of bufsize to the amount of
       buffer space used.  When the parameters buf and bufsize are set to NULL
       and zero, respectively; it returns 0 and sets the value of  bufsize  to
       the amount of buffer space that needs to be preallocated.

ERRORS
       If  this	 function returns -1 to indicate an error, the global variable
       will be set to one of the following values, to indicate the error  that
       occurred:

	      The specified tunable parameter does not exist.

	      The space in   buf,  as  specified in bufsize, is not sufficient
			     to hold the requested data.

	      tunable,	     buf, or bufsize contains an address that is inac‐
			     cessible.

	      The  Kernel  Registry  Service was unavailable or encountered an
	      error.

	      The	     version is not supported.

EXAMPLES
WARNINGS
       Applications and application modules must not share  structures	unless
       it  is  certain	that the value of specified in the header file, is the
       same for all modules and involved.  The value of may be changed without
       notice.

AUTHOR
       was developed by Hewlett-Packard Company.

SEE ALSO
       kctune(1M), gettune(2), settune(2).

       The individual tunable parameter manpages in section 5.

								  tuneinfo2(2)

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