A DDS_QueryCondition is a specialized DDS_ReadCondition which includes a filter. More...

Related Functions
(Note that these are not member functions.)
unsigned char	DDS_QueryCondition_get_trigger_value (DDS_QueryCondition qc)
	This routine returns the current value of the trigger_value in qc. More...

DDS_DataReader	DDS_QueryCondition_get_datareader (DDS_QueryCondition qc)
	This routine returns the single DDS_DataReader associated with this QueryCondition.

DDS_SampleStateKind	DDS_QueryCondition_get_sample_state_mask (DDS_QueryCondition qc)
	This routine returns the current value of the sample_state in this QueryCondition.

DDS_ViewStateKind	DDS_QueryCondition_get_view_state_mask (DDS_QueryCondition qc)
	This routine returns the current value of the view_state in this QueryCondition.

DDS_InstanceStateKind	DDS_QueryCondition_get_instance_state_mask (DDS_QueryCondition qc)
	This routine returns the current value of the instance_state in this QueryCondition.

const char *	DDS_QueryCondition_get_query_expression (DDS_QueryCondition qc)
	This routine returns the SQL query expression of this QueryCondition. More...

DDS_ReturnCode_t	DDS_QueryCondition_get_query_parameters (DDS_QueryCondition qc, DDS_StringSeq *seq)
	This routine returns the parameters to the SQL query expression of this QueryCondition. More...

DDS_ReturnCode_t	DDS_QueryCondition_set_query_parameters (DDS_QueryCondition qc, DDS_StringSeq *parameters)
	This routine sets the parameters to the SQL query expression of this QueryCondition. More...

Detailed Description

A DDS_QueryCondition is a specialized DDS_ReadCondition which includes a filter.

The trigger_value is driven by the data available, after applying the filter, in the associated DataReader.

Not Yet Supported:: CoreDX DDS does not yet implement QueryConditions as a trigger for a WaitSet.

Friends And Related Function Documentation

◆ DDS_QueryCondition_get_query_expression()

const char * DDS_QueryCondition_get_query_expression ( DDS_QueryCondition qc )

The query expression is an SQL syntax conditional expression that is provided when the QueryCondition is created.

◆ DDS_QueryCondition_get_query_parameters()

DDS_ReturnCode_t DDS_QueryCondition_get_query_parameters	(	DDS_QueryCondition	qc,
		DDS_StringSeq *	seq
	)

The query expression is an SQL syntax conditional expression that is provided when the QueryCondition is created. The query expression may contain references to positional parameters of the form '%0', '%1'. These parameters can be changed dynamically to affect the expression.

See also: DDS_DataReader_create_querycondition(); DDS_QueryCondition_set_query_parameters()

◆ DDS_QueryCondition_get_trigger_value()

unsigned char DDS_QueryCondition_get_trigger_value ( DDS_QueryCondition qc )

A non-zero return value indicates that the trigger_value is TRUE.

A zero return value indicates that the trigger_value is FALSE.

◆ DDS_QueryCondition_set_query_parameters()

DDS_ReturnCode_t DDS_QueryCondition_set_query_parameters	(	DDS_QueryCondition	qc,
		DDS_StringSeq *	parameters
	)

The query_expression is an SQL like condition expression, and the parameters argument provides optional parameters that are referenced by the query_expression. The syntax for refering to paramters in a query_expression is the percent sign '' followed by a number. The number is the index of the paramter in the query_paramters sequence. Parameters are counted starting at zero. So, "%0" refers to the first parameter, and "%4" refers to the fifth paramter. Using this syntax, the expression "x<%0" would test the value of 'x' against the first parameter in the sequence.

This routine allows the parameters to be changed dynamically.

See also: DDS_DataReader_create_querycondition()