scc::util::Event Class Reference

Signaling kernel event counter. More...

#include <event.h>

Public Types
enum	EventFlag { nonblocking = 1 , semaphore = 2 }
	Event flags. More...

Public Member Functions
	Event (int=0)
	Construct an event. More...
	Event (const Event &)=delete
	No copy.
void	operator= (const Event &)=delete
	No copy.
	Event (Event &&other)
	Move constructor.
const Event &	operator= (Event &&other)
	Move assignment.
	operator int () const
	Cast object to int.
int	fd () const
	Return file descriptor. More...
void	reset (int=-1)
	Reset the event. More...
uint64_t	read ()
	Read from (decrement) the event counter. More...
void	write (uint64_t)
	Write to (increment) the event counter. More...

Detailed Description

Signaling kernel event counter.

Writes increment the event counter.

Sempahore mode means reads will decrement the counter by 1. Otherwise, reads reset the counter to 0.

Non-blocking mode means the event can throw an exception (EAGAIN) if called when not signalled. The event should probably be polled in this case. See: Kernel file descriptor event notification poller

Examples

examples/net/netmain.cc, net/unittest/inet.cc, net/unittest/inet_stream.cc, net/unittest/unix.cc, util/unittest/event.cc, and util/unittest/poller.cc.

Definition at line 78 of file event.h.

Member Enumeration Documentation

EventFlag

enum scc::util::Event::EventFlag

Event flags.

Enumerator
nonblocking	Non-blocking mode. If an event is read while unsignalled, throws and exception.
semaphore	Semaphore mode. Event reads decrement the counter by 1. Otherwise, reads set the counter to 0.

Definition at line 86 of file event.h.

Constructor & Destructor Documentation

Event()

Event::Event

(

int

flags = 0

)

Construct an event.

Parameters

flags

Event flags, see: EventFlag

Definition at line 45 of file event.cc.

Member Function Documentation

fd()

int scc::util::Event::fd ( ) const

inline

Return file descriptor.

-1 for invalid object.

Definition at line 122 of file event.h.

read()

uint64_t Event::read

(

)

Read from (decrement) the event counter.

For blocking event, blocks until counter becomes signalled (non-zero). For a non-blocking event, throws an exception if the counter is not signalled.

For a semaphore, returns 1 and decrements counter by 1. Otherwise, returns the counter value and sets counter to 0.

Examples

net/unittest/inet.cc.

Definition at line 82 of file event.cc.

reset()

void Event::reset

(

int

flags = -1

)

Reset the event.

Reset the event to unsignalled state (counter 0).

Parameters

flags

if >= 0, override the event flags, otherwise, reset to original flags. See: EventFlag

Examples

net/unittest/inet.cc.

Definition at line 63 of file event.cc.

write()

void Event::write

(

uint64_t

v

)

Write to (increment) the event counter.

Parameters

v	Increments the event counter by the value.

Examples

net/unittest/inet.cc.

Definition at line 94 of file event.cc.

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

• util/pub/util/event.h
• util/event.cc