.TH LDAP_FIRST_ATTRIBUTE 3 "RELEASEDATE" "OpenLDAP LDVERSION"
.\" $OpenLDAP$
.\" Copyright 1998-2021 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
.SH NAME
ldap_first_attribute, ldap_next_attribute \- step through LDAP entry attributes
.SH LIBRARY
OpenLDAP LDAP (libldap, \-lldap)
.SH SYNOPSIS
.nf
.ft B
#include <ldap.h>
.LP
.ft B
char *ldap_first_attribute(
	LDAP *ld, LDAPMessage *entry, BerElement **berptr )
.LP
.ft B
char *ldap_next_attribute(
	LDAP *ld, LDAPMessage *entry, BerElement *ber )
.LP
.ft B
int ldap_get_attribute_ber(
	LDAP *ld, LDAPMessage *entry, BerElement *ber,
	BerValue *attr, BerVarray *vals )
.SH DESCRIPTION
The
.BR ldap_first_attribute() ,
.B ldap_next_attribute()
and
.B ldap_get_attribute_ber()
routines are used
to step through the attributes in an LDAP entry.
.B ldap_first_attribute()
takes an \fIentry\fP as returned by
.BR ldap_first_entry (3)
or
.BR ldap_next_entry (3)
and returns a pointer to character string
containing the first attribute description in the entry.
.B ldap_next_attribute()
returns the next attribute description in the entry.
.LP
It also returns, in \fIberptr\fP, a pointer to a BerElement it has
allocated to keep track of its current position.  This pointer should
be passed to subsequent calls to
.B ldap_next_attribute()
and is used
to effectively step through the entry's attributes.  The caller is
solely responsible for freeing the BerElement pointed to by \fIberptr\fP
when it is no longer needed by calling
.BR ber_free (3).
When calling
.BR ber_free (3)
in this instance, be sure the second argument is 0.
.LP
The attribute names returned are suitable for inclusion in a call
to
.BR ldap_get_values (3)
to retrieve the attribute's values.
.LP
The
.B ldap_get_attribute_ber()
routine allows one to iterate over all attributes in-place, without
allocating memory to hold text for the attribute name or its values,
if requested. The use case is similar to
.B ldap_next_attribute()
except that the attribute name is returned into \fIattr\fP and, if
\fIvals\fP is non-NULL, the list of values is stored there. Both point
into the LDAP message and remain valid only while the entry is valid.
The caller is still responsible for freeing \fIvals\fP with
.BR ldap_memfree (3),
if used.
.SH ERRORS
If an error occurs, NULL is returned and the ld_errno field in the
\fIld\fP parameter is set to indicate the error.  See
.BR ldap_error (3)
for a description of possible error codes.
.SH NOTES
The
.B ldap_first_attribute()
and
.B ldap_next_attribute()
return dynamically allocated memory that must be freed by the caller via
.BR ldap_memfree (3).
For
.BR ldap_get_attribute_ber() ,
only the actual \fIvals\fP pointer needs to be freed with
.BR ldap_memfree (3),
other data is accounted for as part of \fIber\fP.
.SH SEE ALSO
.BR ldap (3),
.BR ldap_first_entry (3),
.BR ldap_get_values (3),
.BR ldap_error (3)
.SH ACKNOWLEDGEMENTS
.so ../Project