genders_query(3)

1GENDERS_QUERY(3)                  LIBGENDERS                  GENDERS_QUERY(3)
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NAME

6       genders_query - query genders database for a set of nodes
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SYNOPSIS

9       #include <genders.h>
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11       int  genders_query(genders_t handle, char *nodes[], int len, const char
12       *query);
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DESCRIPTION

15       genders_query() queries the genders database for a set of  nodes  based
16       on  the  union,  intersection,  difference,  or  complement  of genders
17       attributes and values.  The query for a set of nodes  is  passed  as  a
18       string  through the query parameter.  The set operation union is repre‐
19       sented by two pipe symbols ('||'), intersection by two  ampersand  sym‐
20       bols  ('&&'), difference by two minus symbols ('--'), and complement by
21       a tilde ('~').  Set operations are performed left to right.   Parenthe‐
22       ses  may  be  used  to change the order of operations.  A list of query
23       examples are listed below.  A NULL query retrieves all nodes  from  the
24       genders database.
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26       The  nodes  from  the query are stored in the list pointed to by nodes.
27       len indicates the number of nodes that can be stored in the list.
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29       To avoid passing in a list that is not large enough to  store  all  the
30       nodes,  genders_getnumnodes(3)  should be used to determine the minimum
31       number  of  elements   nodes   should   be   able   to   store.    gen‐
32       ders_nodelist_create(3)  could be used to create a list that is guaran‐
33       teed to be large enough to store all of the nodes.
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EXAMPLES

36       The  following  are  example  queries  that  can  be  passed  to   gen‐
37       ders_query().
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39       Determine the set of nodes with the mgmt or login attribute:
40               "mgmt||login"
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42       Determine the set of nodes that are not login nodes:
43               "all--login"
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45       Determine the set of nodes that both login nodes and ntp servers:
46               "login&&ntpserv"
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48       Determine the set of nodes that are not mgmt or login nodes:
49               "~(mgmt||login)"
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RETURN VALUES

52       On success, the number of nodes stored in nodes is returned.  On error,
53       -1 is returned, and an error code is returned  in  handle.   The  error
54       code  can be retrieved via genders_errnum(3) , and a description of the
55       error code can be retrieved via genders_strerror(3).  Error  codes  are
56       defined in genders.h.
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ERRORS

59       GENDERS_ERR_NULLHANDLE
60              The  handle  parameter is NULL.  The genders handle must be cre‐
61              ated with genders_handle_create(3).
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63       GENDERS_ERR_NOTLOADED
64              genders_load_data(3) has not been called to load genders data.
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66       GENDERS_ERR_OVERFLOW
67              The list pointed to by nodes is not large enough  to  store  all
68              the nodes.
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70       GENDERS_ERR_PARAMETERS
71              An incorrect parameter has been passed in.
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73       GENDERS_ERR_SYNTAX
74              There is a syntax error in the query.
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76       GENDERS_ERR_OUTMEM
77              malloc(3) has failed internally, system is out of memory.
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79       GENDERS_ERR_NULLPTR
80              A null pointer has been found in the list passed in.
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82       GENDERS_ERR_MAGIC
83              handle  has an incorrect magic number.  handle does not point to
84              a genders handle or handle has been  destroyed  by  genders_han‐
85              dle_destroy(3).
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87       GENDERS_ERR_INTERNAL
88              An internal system error has occurred.
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FILES

91       /usr/include/genders.h
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