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LDAP_SORT(3)
NAME
  ldap_sort_entries, ldap_sort_values, ldap_sort_strcasecmp - LDAP sorting
  routines

SYNOPSIS
  #include <ldap.h>

  ldap_sort_entries(ld, chain, attr, cmp)
  LDAP *ld;
  LDAPMessage **chain;
  char *attr;
  int (*cmp)();

  ldap_sort_values(ld, vals, cmp)
  LDAP *ld;
  char **vals;
  int (*cmp)();

  ldap_sort_strcasecmp(a, b)
  char *a;
  char *b;

DESCRIPTION
  These routines are used to sort lists of entries and values retrieved from
  an LDAP server.  ldap_sort_entries() is used to sort a chain of entries
  retrieved from an LDAP search call either by DN or by some arbitrary
  attribute in the entries.  It takes ld, the LDAP structure, which is only
  used for error reporting, chain, the list of entries as returned by
  ldap_search_s(3) or ldap_result(3).  attr is the attribute to use as a key
  in the sort or NULL to sort by DN, and cmp is the comparison function to
  use when comparing values (or individual DN components if sorting by DN).
  In this case, cmp should be a function taking two single values of the attr
  to sort by, and returning a value less than zero, equal to zero, or greater
  than zero, depending on whether the first argument is less than, equal to,
  or greater than the second argument.	The convention is the same as used by
  qsort(3), which is called to do the actual sorting.

  ldap_sort_values() is used to sort an array of values from an entry, as
  returned by ldap_get_values(3).  It takes the LDAP connection structure ld,
  the array of values to sort vals, and cmp, the comparison function to use
  during the sort.  Note that cmp will be passed a pointer to each element in
  the vals array, so if you pass the normal char ** for this parameter, cmp
  should take two char **'s as arguments (i.e., you cannot pass strcasecmp or
  its friends for cmp).	 You can, however, pass the function
  ldap_sort_strcasecmp() for this purpose.

  For example:

	  LDAP *ld;
	  LDAPMessage *res;

	  /* ... call to ldap_search_s(), fill in res, retrieve sn attr ... */

	  /* now sort the entries on surname attribute */
	  if ( ldap_sort_entries( ld, &res, "sn", ldap_sort_strcasecmp ) != 0 )
		  ldap_perror( ld, "ldap_sort_entries" );

NOTES
  The ldap_sort_entries() routine applies the comparison function to each
  value of the attribute in the array as returned by a call to
  ldap_get_values(3), until a mismatch is found.  This works fine for
  single-valued attributes, but may produce unexpected results for multi-
  valued attributes.  When sorting by DN, the comparison function is applied
  to an exploded version of the DN, without types.  The return values for all
  of these functions are declared in the <ldap.h> header file.	Some routines
  may dynamically allocate memory.  Callers are responsible for freeing such
  memory using the supplied deallocation routines.

SEE ALSO
  ldap(3), ldap_search(3), ldap_result(3), qsort(3)

ACKNOWLEDGEMENTS
	OpenLDAP is developed and maintained by The OpenLDAP Project
  (http://www.openldap.org/).	     OpenLDAP is derived from University of
  Michigan LDAP 3.3 Release.

Index for Section 3

Alphabetical listing for L

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