knlist(3)						     Library Functions Manual							 knlist(3)

NAME

       knlist - Look up symbols in the currently running kernel

LIBRARY

       Standard C Library (libc.a, libc.so)

SYNOPSIS

       #include <nlist.h>
	int knlist(
		 struct nlist namelist);

PARAMETERS

       On  input, lists the symbol names for which you are requesting addresses. The namelist must be terminated with a null name at end.  Without
       a terminating null name at end, knlist() cannot determine how many symbols there are in the namelist and  therefore it may dump core.

	      On return, contains a list of symbol addresses (or 0 if the attempt to find the addresses was unsuccessful).

DESCRIPTION

       The knlist() library routine looks up addresses of kernel symbols in the currently running kernel.  In addition to finding symbols  associ-
       ated with the kernel image, knlist() will also find symbols defined in dynamically loaded subsystems.

       Communication  with  the  knlist() routine occurs using an array of type struct nlist. The <nlist.h> header file declares that type as fol-
       lows: struct nlist{
	   char *n_name;
	   unsigned long n_value;
	   short n_type;	       /* 0 if not there, 1 if found */
	   short reserved; };

       When your application calls knlist() it passes the names of symbols in the n_name field of the structure.

       For each symbol, the knlist() routine attempts to determine its current address in memory.  If the routine can determine the address of the
       symbol,	it  returns  that  address  in the n_value field, and it returns one(1) in the n_type field.  If the routine cannot determine the
       address, it returns zero(0) in both the n_value field and the n_type field.

       For BSD compatibility, the knlist routine allows symbol names to be preceded by an underscore.  If it does not find a symbol  that  matches
       the name as specified, knlist attempts to locate the symbol name with the leading underscore removed.

EXAMPLES

       The  following  example	illustrates  the  use of the knlist() routine: #include <stdio.h> #include <string.h> #include <stdlib.h> #include
       <nlist.h> main () {
	  struct nlist	 nl[3];
	  int		 retval, i;
	  nl[0].n_name = (char *)malloc(10);
	  nl[1].n_name = (char *)malloc(10);
	  nl[2].n_name = "";

	  /*******************************************************/
	  /* Store names of kernel symbols in the nl array	 */
	  strcpy (nl[0].n_name, "ncpus");
	  strcpy (nl[1].n_name, "lockmode");

	  /*******************************************************/
	  /* Call the knlist routine				 */
	  retval = knlist(nl);

	  /******************************************************/
	  /* Display addresses if returned.  Otherwise, display */
	  /* the appropriate error message.			*/
	  if (retval < 0)
	     printf ("No kernel symbol addresses returned.
");
	  else
	     if (retval >= 0 )
		for (i=0; i<2; i++)
		    if (nl[i].n_type == 0)
			printf ("Unable to return address of symbol %s
",
				nl[i].n_name);
		    else
			printf ("The address of symbol %s is %lx
",
				nl[i].n_name, nl[i].n_value);
	  free (nl[0].n_name);
	  free (nl[1].n_name); }

       This example tests the return value from the knlist() routine.  If the routine returns an error status,	a  message  is	displayed  to  the
       application  user.  Otherwise,  the  application  checks  the status of each kernel symbol. If the knlist() routine was unable to return an
       address, the application displays a message and the symbol name.  If the knlist() routine returns an address, the application displays  the
       symbol name and address to the application user.

RETURN VALUES

       The  knlist()  routine  returns zero on success.  The routine returns -1 if it was unable to connect to the kloadsrv daemon.  In this case,
       the routine was unable to determine any of the requested addresses.  The routine returns a positive integer if it successfully  finds  some
       addresses and fails to find others.  The integer value indicates the number of addresses knlist() was unable to return.

       The routine returns the negative value of EINVAL if the argument is bad.

RELATED INFORMATION

       Routines:  nlist(3) delim off

																	 knlist(3)