RTI Connext C API
Version 5.3.0
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DDS_QueryCondition and associated elements More...
Data Structures | |
struct | DDS_QueryConditionParams |
<<extension>> Input parameters for DDS_DataReader_create_querycondition_w_params More... | |
Typedefs | |
typedef struct DDS_QueryConditionImpl | DDS_QueryCondition |
<<interface>> These are specialised DDS_ReadCondition objects that allow the application to also specify a filter on the locally available data. | |
Functions | |
DDS_ReadCondition * | DDS_QueryCondition_as_readcondition (DDS_QueryCondition *query_condition) |
Access a DDS_QueryCondition's supertype instance. | |
const char * | DDS_QueryCondition_get_query_expression (DDS_QueryCondition *self) |
Retrieves the query expression. | |
DDS_ReturnCode_t | DDS_QueryCondition_get_query_parameters (DDS_QueryCondition *self, struct DDS_StringSeq *query_parameters) |
Retrieves the query parameters. | |
DDS_ReturnCode_t | DDS_QueryCondition_set_query_parameters (DDS_QueryCondition *self, const struct DDS_StringSeq *query_parameters) |
Sets the query parameters. | |
DDS_QueryCondition and associated elements
typedef struct DDS_QueryConditionImpl DDS_QueryCondition |
<<interface>> These are specialised DDS_ReadCondition objects that allow the application to also specify a filter on the locally available data.
Each query condition filter is composed of a DDS_ReadCondition state filter and a content filter expressed as a query_expression
and query_parameters
.
The query (query_expression
) is similar to an SQL WHERE clause and can be parameterised by arguments that are dynamically changeable by the set_query_parameters() operation.
Two query conditions that have the same query_expression
will require unique query condition content filters if their query_paramters
differ. Query conditions that differ only in their state masks will share the same query condition content filter.
Queries and Filters Syntax describes the syntax of query_expression
and query_parameters
.
DDS_ReadCondition* DDS_QueryCondition_as_readcondition | ( | DDS_QueryCondition * | query_condition | ) |
Access a DDS_QueryCondition's supertype instance.
query_condition | <<in>> Cannot be NULL. |
const char* DDS_QueryCondition_get_query_expression | ( | DDS_QueryCondition * | self | ) |
Retrieves the query expression.
self | <<in>> Cannot be NULL. |
DDS_ReturnCode_t DDS_QueryCondition_get_query_parameters | ( | DDS_QueryCondition * | self, |
struct DDS_StringSeq * | query_parameters | ||
) |
Retrieves the query parameters.
query_parameters | <<inout>> the query parameters are returned here. The memory for the strings in this sequence is managed according to the conventions described in Conventions. In particular, be careful to avoid a situation in which RTI Connext allocates a string on your behalf and you then reuse that string in such a way that RTI Connext believes it to have more memory allocated to it than it actually does. |
self | <<in>> Cannot be NULL. |
DDS_ReturnCode_t DDS_QueryCondition_set_query_parameters | ( | DDS_QueryCondition * | self, |
const struct DDS_StringSeq * | query_parameters | ||
) |