Section: C Library Functions (3)
Updated: 2006/08/19
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ldap_result - Wait for the result of an LDAP operation  


OpenLDAP LDAP (libldap, -lldap)  


#include <ldap.h>

int ldap_result( LDAP *ld, int msgid, int all,
        struct timeval *timeout, LDAPMessage **result );

int ldap_msgfree( LDAPMessage *msg );

int ldap_msgtype( LDAPMessage *msg );

int ldap_msgid( LDAPMessage *msg );


The ldap_result() routine is used to wait for and return the result of an operation previously initiated by one of the LDAP asynchronous operation routines (e.g., ldap_search(3), ldap_modify(3), etc.). Those routines all return -1 in case of error, and an invocation identifier upon successful initiation of the operation. The invocation identifier is picked by the library and is guaranteed to be unique across the LDAP session. It can be used to request the result of a specific operation from ldap_result() through the msgid parameter.

The ldap_result() routine will block or not, depending upon the setting of the timeout parameter. If timeout is not a NULL pointer, it specifies a maximum interval to wait for the selection to complete. If timeout is a NULL pointer, the select blocks indefinitely. To effect a poll, the timeout argument should be a non-NULL pointer, pointing to a zero-valued timeval structure. See select(2) for further details.

If the result of a specific operation is required, msgid should be set to the invocation identifier returned when the operation was initiated, otherwise LDAP_RES_ANY or LDAP_RES_UNSOLICITED should be supplied to wait for any or unsolicited response.

The all parameter, if non-zero, causes ldap_result() to return all responses with msgid, otherwise only the next response is returned. This is commonly used to obtain all the responses of a search operation.

A search response is made up of zero or more search entries, zero or more search references, and zero or more extended partial responses followed by a search result. If all is set to 0, search entries will be returned one at a time as they come in, via separate calls to ldap_result(). If it's set to 1, the search response will only be returned in its entirety, i.e., after all entries, all references, all extended partial responses, and the final search result have been received.

Upon success, the type of the result received is returned and the result parameter will contain the result of the operation. This result should be passed to the LDAP parsing routines, ldap_first_message(3) and friends, for interpretation.

The possible result types returned are:

        LDAP_RES_BIND (0x61)
        LDAP_RES_SEARCH_ENTRY (0x64)
        LDAP_RES_MODIFY (0x67)
        LDAP_RES_ADD (0x69)
        LDAP_RES_DELETE (0x6b)
        LDAP_RES_MODDN (0x6d)
        LDAP_RES_COMPARE (0x6f)
        LDAP_RES_EXTENDED (0x78)

The ldap_msgfree() routine is used to free the memory allocated for result(s) by ldap_result() or ldap_search_s(3) and friends. It takes a pointer to the result or result chain to be freed and returns the type of the last message in the chain. If the parameter is NULL, the function does nothing and returns zero.

The ldap_msgtype() routine returns the type of a message.

The ldap_msgid() routine returns the message id of a message.  


ldap_result() returns -1 if something bad happens, and zero if the timeout specified was exceeded. ldap_msgtype() and ldap_msgid() return -1 on error.  


ldap(3), ldap_search(3), ldap_first_message(3), select(2)  


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




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