# 9.4. ODPI-C Dequeue Options Functions

Dequeue option handles are used to represent the options specified when dequeuing messages using advanced queueing. They are created by calling the function `dpiConn_newDeqOptions()` and are destroyed by releasing the last reference by calling the function `dpiDeqOptions_release()`.

int dpiDeqOptions_addRef(dpiDeqOptions *options)

  Adds a reference to the dequeue options. This is intended for situations where a reference to the dequeue options needs to be maintained independently of the reference returned when the handle was created.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | The dequeue options to which a reference is to be added. If the reference is NULL or invalid, an error is returned.

int dpiDeqOptions_getCondition(dpiDeqOptions *options, const char **value, uint32_t *valueLength)

  Returns the condition that must be satisfied in order for a message to be dequeued. See function `dpiDeqOptions_setCondition()` for more information.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the condition is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, as a byte string in the encoding used for CHAR data, which will be populated upon successful completion of this function. If there is no condition, the pointer will be populated with the value NULL.
  `valueLength` | OUT | A pointer to the length of the value, in bytes, which will be populated upon successful completion of this function. If there is no condition, the pointer will be populated with the value 0.

int dpiDeqOptions_getConsumerName(dpiDeqOptions *options, const char **value, uint32_t *valueLength)

  Returns the name of the consumer that is dequeuing messages. See function `dpiDeqOptions_setConsumerName()` for more information.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the consumer name is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, as a byte string in the encoding used for CHAR data, which will be populated upon successful completion of this function. If there is no consumer name, the pointer will be populated with the value NULL.
  `valueLength` | OUT | A pointer to the length of the value, in bytes, which will be populated upon successful completion of this function. If there is no consumer name, the pointer will be populated with the value 0.

int dpiDeqOptions_getCorrelation(dpiDeqOptions *options, const char **value, uint32_t *valueLength)

  Returns the correlation of the message to be dequeued. See function `dpiDeqOptions_setCorrelation()` for more information.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the correlation is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, as a byte string in the encoding used for CHAR data, which will be populated upon successful completion of this function. If there is no correlation, the pointer will be populated with the value NULL.
  `valueLength` | OUT | A pointer to the length of the value, in bytes, which will be populated upon successful completion of this function. If there is no correlation, the pointer will be populated with the value 0.

int dpiDeqOptions_getMode(dpiDeqOptions *options, dpiDeqMode *value)

  Returns the mode that is to be used when dequeuing messages.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the mode is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, which will be populated upon successful completion of this function. It will be one of the values from the enumeration dpiDeqMode.

int dpiDeqOptions_getMsgId(dpiDeqOptions *options, const char **value, uint32_t *valueLength)

  Returns the identifier of the specific message that is to be dequeued.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the message identifier is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, which will be populated upon successful completion of this function. If there is no message identifier, the pointer will be populated with the value NULL.
  `valueLength` | OUT | A pointer to the length of the value, in bytes, which will be populated upon successful completion of this function. If there is no message identifier, the pointer will be populated with the value 0.

int dpiDeqOptions_getNavigation(dpiDeqOptions *options, dpiDeqNavigation *value)

  Returns the position of the message that is to be dequeued.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the navigation option is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, which will be populated upon successful completion of this function. It will be one of the values from the enumeration dpiDeqNavigation.

int dpiDeqOptions_getTransformation(dpiDeqOptions *options, const char **value, uint32_t *valueLength)

  Returns the transformation of the message to be dequeued. See function `dpiDeqOptions_setTransformation()` for more information.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the transformation is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, as a byte string in the encoding used for CHAR data, which will be populated upon successful completion of this function. If there is no transformation, the pointer will be populated with the value NULL.
  `valueLength` | OUT | A pointer to the length of the value, in bytes, which will be populated upon successful completion of this function. If there is no transformation, the pointer will be populated with the value 0.

int dpiDeqOptions_getVisibility(dpiDeqOptions *options, dpiVisibility *value)

  Returns whether the message being dequeued is part of the current transaction or constitutes a transaction on its own.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the visibility is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, which will be populated upon successful completion of this function. It will be one of the values from the enumeration dpiVisibility.

int dpiDeqOptions_getWait(dpiDeqOptions *options, uint32_t *value)

  Returns the time to wait, in seconds, for a message matching the search criteria. See function `dpiDeqOptions_setWait()` for more information.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options from which the wait time is to be retrieved. If the reference is NULL or invalid, an error is returned.
  `value` | OUT | A pointer to the value, which will be populated upon successful completion of this function.

int dpiDeqOptions_release(dpiDeqOptions *options)

  Releases a reference to the dequeue options. A count of the references to the dequeue options is maintained and when this count reaches zero, the memory associated with the options is freed.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | The dequeue options from which a reference is to be released. If the reference is NULL or invalid, an error is returned.

int dpiDeqOptions_setCondition(dpiDeqOptions *options, const char *value, uint32_t valueLength)

  Sets the condition which must be true for messages to be dequeued. The condition must be a valid boolean expression similar to the where clause of a SQL query. The expression can include conditions on message properties, user data properties and PL/SQL or SQL functions. User data properties must be prefixed with tab.user_data as a qualifier to indicate the specific column of the queue table that stores the message payload.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the condition is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | A byte string in the encoding used for CHAR data, or NULL if the condition is to be cleared.
  `valueLength` | IN | The length of the value parameter in bytes, or 0 if the value parameter is NULL.

int dpiDeqOptions_setConsumerName(dpiDeqOptions *options, const char *value, uint32_t valueLength)

  Sets the name of the consumer which will be dequeuing messages. This value should only be set if the queue is set up for multiple consumers.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the consumer name is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | A byte string in the encoding used for CHAR data, or NULL if the consumer name is to be cleared.
  `valueLength` | IN | The length of the value parameter in bytes, or 0 if the value parameter is NULL.

int dpiDeqOptions_setCorrelation(dpiDeqOptions *options, const char *value, uint32_t valueLength)

  Sets the correlation of the message to be dequeued. Special pattern matching characters such as the percent sign (%) and the underscore (_) can be used. If multiple messages satisfy the pattern, the order of dequeuing is undetermined.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the correlation is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | A byte string in the encoding used for CHAR data, or NULL if the correlation is to be cleared.
  `valueLength` | IN | The length of the value parameter in bytes, or 0 if the value parameter is NULL.

int dpiDeqOptions_setDeliveryMode(dpiDeqOptions *options, dpiMessageDeliveryMode value)

  Sets the message delivery mode that is to be used when dequeuing messages.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the message delivery mode is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | The mode that should be used. It should be one of the values from the enumeration dpiMessageDeliveryMode.

int dpiDeqOptions_setMode(dpiDeqOptions *options, dpiDeqMode value)

  Sets the mode that is to be used when dequeuing messages.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the mode is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | The mode that should be used. It should be one of the values from the enumeration dpiDeqMode.

int dpiDeqOptions_setMsgId(dpiDeqOptions *options, const char *value, uint32_t valueLength)

  Sets the identifier of the specific message to be dequeued.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the message identifier is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | A pointer to the bytes making up the message identifier, or NULL if no specific message is to be dequeued.
  `valueLength` | IN | The length of the value parameter in bytes, or 0 if the value parameter is NULL.

int dpiDeqOptions_setNavigation(dpiDeqOptions *options, dpiDeqNavigation value)

  Sets the position in the queue of the message that is to be dequeued.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the navigation option is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | The value that should be used. It should be one of the values from the enumeration dpiDeqNavigation.

int dpiDeqOptions_setTransformation(dpiDeqOptions *options, const char *value, uint32_t valueLength)

  Sets the transformation of the message to be dequeued. The transformation is applied after the message is dequeued but before it is returned to the application. It must be created using DBMS_TRANSFORM.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the transformation is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | A byte string in the encoding used for CHAR data, or NULL if the transformation is to be cleared.
  `valueLength` | IN | The length of the value parameter in bytes, or 0 if the value parameter is NULL.

int dpiDeqOptions_setVisibility(dpiDeqOptions *options, dpiVisibility value)

  Sets whether the message being dequeued is part of the current transaction or constitutes a transaction on its own.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the visibility is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | The value that should be used. It should be one of the values from the enumeration dpiVisibility.

int dpiDeqOptions_setWait(dpiDeqOptions *options, uint32_t value)

  Set the time to wait, in seconds, for a message matching the search criteria.

  The function returns DPI_SUCCESS for success and DPI_FAILURE for failure.

  Parameter | Mode | Description
  --- | --- | ---
  `options` | IN | A reference to the dequeue options on which the wait time is to be set. If the reference is NULL or invalid, an error is returned.
  `value` | IN | The number of seconds to wait for a message matching the search criteria. Any integer is valid but the predefined constants DPI_DEQ_WAIT_NO_WAIT and DPI_DEQ_WAIT_FOREVER are provided as a convenience.