bionic (3) genders_query.3.gz

Provided by: libgenders0-dev_1.21-1build5_amd64 bug

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 represented 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_handle_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), genders_strerror(3)