NAL_SELECTOR_NEW(2) distcache NAL_SELECTOR_NEW(2)NAME
NAL_SELECTOR_new, NAL_SELECTOR_free, NAL_SELECTOR_select - libnal
selector functions
SYNOPSIS
#include <libnal/nal.h>
NAL_SELECTOR *NAL_SELECTOR_new(void);
void NAL_SELECTOR_free(NAL_SELECTOR *sel);
int NAL_SELECTOR_select(NAL_SELECTOR *sel, unsigned long usec_timeout,
int use_timeout);
DESCRIPTIONNAL_SELECTOR_new() allocates and initialises a new NAL_SELECTOR object.
NAL_SELECTOR_free() destroys a NAL_SELECTOR object.
NAL_SELECTOR_select() blocks until the selector sel receives notifica‐
tion of network events for which it has registered interest. This func‐
tion blocks indefinitely until receipt of a network event, interruption
by the system, or if use_timeout is non-zero, then the function will
break if more than usec_timeout microseconds have passed. See "NOTES".
RETURN VALUESNAL_SELECTOR_new() returns a valid NAL_SELECTOR object on success, NULL
otherwise.
NAL_SELECTOR_free() has no return value.
NAL_SELECTOR_select() returns negative for an error, otherwise it
returns the number of connections and/or listeners that the selector
has detected have network events waiting (which can be zero).
NOTES
The NAL_SELECTOR allows the caller to register NAL_CONNECTION and
NAL_LISTENER objects for any events appropriate to them and then block
execution with NAL_SELECTOR_select() until there are events that need
processing. The exact semantics NAL_CONNECTION_add_to_selector() and
NAL_LISTENER_add_to_selector() are documented in other manual pages,
see "NOTES".
The behaviour of NAL_SELECTOR_select() is what one would normally
expect from a system select(2) function. On error, the return value is
negative. Otherwise the return value is the number of connection and/or
listener objects that have network events waiting for them. A return
value of zero is possible if the function breaks before any network
events have arrived, eg. if use_timeout was specified, or if a
unblocked signal arrived. In such cases, subsequent calls to NAL_CON‐
NECTION_io() and NAL_LISTENER_accept() will trivially return without
performing any actions as the selector has no events registered for
processing. As such, if NAL_SELECTOR_select() returns zero, it is gen‐
erally advised to add the connections and listeners back to the selec‐
tor object and call NAL_SELECTOR_select() again.
As with other libnal functions, `errno' is not touched so that any
errors in the system's underlying implementations can be investigated
directly by the calling application.
SEE ALSONAL_ADDRESS_new(2) - Functions for the NAL_ADDRESS type.
NAL_CONNECTION_new(2) - Functions for the NAL_CONNECTION type.
NAL_LISTENER_new(2) - Functions for the NAL_LISTENER type.
NAL_BUFFER_new(2) - Functions for the NAL_BUFFER type.
distcache(8) - Overview of the distcache architecture.
http://www.distcache.org/ - Distcache home page.
AUTHOR
This toolkit was designed and implemented by Geoff Thorpe for Crypto‐
graphic Appliances Incorporated. Since the project was released into
open source, it has a home page and a project environment where devel‐
opment, mailing lists, and releases are organised. For problems with
the software or this man page please check for new releases at the
project web-site below, mail the users mailing list described there, or
contact the author at geoff@geoffthorpe.net.
Home Page: http://www.distcache.org
1.4.5 2004.03.23 NAL_SELECTOR_NEW(2)
