PdCom::Variable::Subscription Class Reference

Subscription class. More...

#include <Variable.h>

Public Member Functions
	Subscription (Process *process, int id, const Variable *v, int decimation, const uint64_t *const *time, const char *const *data)
	Constructor.
virtual void	cancel () const =0
	Cancel subscription. More...
bool	poll () const
	Poll a subscription. More...
template<typename T >
void	getValue (T *val, size_t index, size_t nelem) const
	Retrieve subscriptions value in any data type. More...
std::string	getStringValue (char delimiter=',') const
	Get the entire value as a linear string. More...
void	print (std::ostream &os, char delimiter) const
	Write the value to std::ostream. More...

Public Attributes
Process *const	process
	pointer to process
const int	id
	id supplied during Process::subscribe()
const Variable *const	variable
	Actual variable.
const int	decimation
	Subscription decimation.
const uint64_t *const *const	time_ns
	Time of value in nanoseconds since epoch. More...

Detailed Description

Subscription class.

The library passes on this class to Subscriber as a result of a successful variable subscribe().

This class is used to query various properties of the Subscription as well as a method to get the variable's value in any data type by calling getValue(), getStringValue() and print().

The value of a subscription is always accessible (doesn't SEGV), but it is not always sensible to call it outside of Subscriber::newValue() or Subscriber::newGroupValue().

To cancel a subscription, issue cancel() on it. cancel() is safe from within newValue() or newGroupValue().

Signals that are subscribed with an intermittent interval < 0 are only updated after issuing poll().

Examples:

example.cpp.

Member Function Documentation

cancel()

virtual void PdCom::Variable::Subscription::cancel ( ) const

pure virtual

Cancel subscription.

Calling cancel() is safe from within Subscriber::newValue() and Subscriber::newGroupValue().

getStringValue()

std::string PdCom::Variable::Subscription::getStringValue

(

char

delimiter = ','

)

const

Get the entire value as a linear string.

Parameters

delimiter

delimiter between vector elements

Examples:

example.cpp.

getValue()

template<typename T >

void PdCom::Variable::Subscription::getValue	(	T *	val,
		size_t	index,
		size_t	nelem
	)		const

Retrieve subscriptions value in any data type.

Parameters

val	value buffer to write to. Must be at least nelem long
index	starting index
nelem	number of elements to retrieve

poll()

bool PdCom::Variable::Subscription::poll

(

)

const

Poll a subscription.

This is only available for signals when request interval < 0, otherwise an error value is returned.

The value is available during Subscriber::newValue().

Returns

true on failure

print()

void PdCom::Variable::Subscription::print	(	std::ostream &	os,
		char	delimiter
	)		const

Write the value to std::ostream.

This allows the user finer control of double variables.

Parameters

os	std::ostream output stream
delimiter	delimiter between vector elements

Member Data Documentation

time_ns

const uint64_t* const* const PdCom::Variable::Subscription::time_ns

Time of value in nanoseconds since epoch.

Use double dereferencing to access the value, eg.

double time = 1.0e-9 * **subscription->time_ns;

Examples:

example.cpp.

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The documentation for this class was generated from the following file:

• /home/abuild/rpmbuild/BUILD/pdcom-4.2.0/pdcom4/Variable.h