GENDERS_QUERY(3)						    LIBGENDERS							  GENDERS_QUERY(3)

NAME

       genders_query - query genders database for a set of nodes

SYNOPSIS

       #include <genders.h>

       int genders_query(genders_t handle, char *nodes[], int len, const char *query);

DESCRIPTION

       genders_query()	queries  the  genders  database  for a set of nodes based on the union, intersection, difference, or complement of genders
       attributes and values.  The query for a set of nodes is passed as a string through the query parameter.	The set operation union is  repre-
       sented  by two pipe symbols ('||'), intersection by two ampersand symbols ('&&'), difference by two minus symbols ('--'), and complement by
       a tilde ('~').  Set operations are performed left to right.  Parentheses may be used to change the order of operations.	A  list  of  query
       examples are listed below.  A NULL query retrieves all nodes from the genders database.

       The nodes from the query are stored in the list pointed to by nodes.  len indicates the number of nodes that can be stored in the list.

       To  avoid passing in a list that is not large enough to store all the nodes, genders_getnumnodes(3) should be used to determine the minimum
       number of elements nodes should be able to store.  genders_nodelist_create(3) could be used to create a list that is guaranteed to be large
       enough to store all of the nodes.

EXAMPLES

       The following are example queries that can be passed to genders_query().

       Determine the set of nodes with the mgmt or login attribute:
	       "mgmt||login"

       Determine the set of nodes that are not login nodes:
	       "all--login"

       Determine the set of nodes that both login nodes and ntp servers:
	       "login&&ntpserv"

       Determine the set of nodes that are not mgmt or login nodes:
	       "~(mgmt||login)"

RETURN VALUES

       On success, the number of nodes stored in nodes is returned.  On error, -1 is returned, and an error code is returned in handle.  The error
       code can be retrieved via genders_errnum(3) , and a description of the error code can be retrieved via  genders_strerror(3).   Error  codes
       are defined in genders.h.

ERRORS

       GENDERS_ERR_NULLHANDLE
	      The handle parameter is NULL.  The genders handle must be created with genders_handle_create(3).

       GENDERS_ERR_NOTLOADED
	      genders_load_data(3) has not been called to load genders data.

       GENDERS_ERR_OVERFLOW
	      The list pointed to by nodes is not large enough to store all the nodes.

       GENDERS_ERR_PARAMETERS
	      An incorrect parameter has been passed in.

       GENDERS_ERR_SYNTAX
	      There is a syntax error in the query.

       GENDERS_ERR_OUTMEM
	      malloc(3) has failed internally, system is out of memory.

       GENDERS_ERR_NULLPTR
	      A null pointer has been found in the list passed in.

       GENDERS_ERR_MAGIC
	      handle  has  an  incorrect  magic  number.   handle  does not point to a genders handle or handle has been destroyed by genders_han-
	      dle_destroy(3).

       GENDERS_ERR_INTERNAL
	      An internal system error has occurred.

FILES

       /usr/include/genders.h

SEE ALSO

       libgenders(3), genders_handle_create(3), genders_load_data(3), genders_getnumnodes(3), genders_nodelist_create(3), genders_errnum(3),  gen-
       ders_strerror(3)

LLNL
								     June 2004							  GENDERS_QUERY(3)