.TH LDAP_SORT 3 "RELEASEDATE" "OpenLDAP LDVERSION" .\" $OpenLDAP: pkg/ldap/doc/man/man3/ldap_sort.3,v 1.11.2.2 2004/01/01 18:16:27 kurt Exp $ .\" Copyright 1998-2004 The OpenLDAP Foundation All Rights Reserved. .\" Copying restrictions apply. See COPYRIGHT/LICENSE. .SH NAME ldap_sort_entries, ldap_sort_values, ldap_sort_strcasecmp \- LDAP sorting routines .SH LIBRARY OpenLDAP LDAP (libldap, -lldap) .SH SYNOPSIS .nf .ft B #include <ldap.h> .LP .ft B ldap_sort_entries(ld, chain, attr, cmp) .ft LDAP *ld; LDAPMessage **chain; char *attr; int (*cmp)(); .LP .ft B ldap_sort_values(ld, vals, cmp) .ft LDAP *ld; char **vals; int (*cmp)(); .LP .ft B ldap_sort_strcasecmp(a, b) .ft char *a; char *b; .SH DESCRIPTION These routines are used to sort lists of entries and values retrieved from an LDAP server. .B 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 \fIld\fP, the LDAP structure, which is only used for error reporting, \fIchain\fP, the list of entries as returned by .BR ldap_search_s (3) or .BR ldap_result (3). \fIattr\fP is the attribute to use as a key in the sort or NULL to sort by DN, and \fIcmp\fP is the comparison function to use when comparing values (or individual DN components if sorting by DN). In this case, \fIcmp\fP should be a function taking two single values of the \fIattr\fP 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 .BR qsort (3), which is called to do the actual sorting. .LP .B ldap_sort_values() is used to sort an array of values from an entry, as returned by .BR ldap_get_values (3). It takes the LDAP connection structure \fIld\fP, the array of values to sort \fIvals\fP, and \fIcmp\fP, the comparison function to use during the sort. Note that \fIcmp\fP will be passed a pointer to each element in the \fIvals\fP array, so if you pass the normal char ** for this parameter, \fIcmp\fP should take two char **'s as arguments (i.e., you cannot pass \fIstrcasecmp\fP or its friends for \fIcmp\fP). You can, however, pass the function .B ldap_sort_strcasecmp() for this purpose. .LP For example: .LP .nf .ft tt 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" ); .ft .fi .SH NOTES .LP The .B ldap_sort_entries() routine applies the comparison function to each value of the attribute in the array as returned by a call to .BR 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. .SH SEE ALSO .BR ldap (3), .BR ldap_search (3), .BR ldap_result (3), .BR qsort (3) .SH ACKNOWLEDGEMENTS .B OpenLDAP is developed and maintained by The OpenLDAP Project (http://www.openldap.org/). .B OpenLDAP is derived from University of Michigan LDAP 3.3 Release.