Manual Reference Pages - NAL_SELECTOR_NEW (2)
NAL_SELECTOR_new, NAL_SELECTOR_free, NAL_SELECTOR_select - libnal selector functions
void NAL_SELECTOR_free(NAL_SELECTOR *sel);
int NAL_SELECTOR_select(NAL_SELECTOR *sel, unsigned long usec_timeout,
NAL_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 notification of
network events for which it has registered interest. This function 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.
NAL_SELECTOR_new() returns a valid NAL_SELECTOR object on success, NULL
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).
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
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_CONNECTION_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 generally
advised to add the connections and listeners back to the selector object and
call NAL_SELECTOR_select() again.
As with other libnal functions, errno is not touched so that any errors in
the systems underlying implementations can be investigated directly by the
NAL_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.
This toolkit was designed and implemented by Geoff Thorpe for Cryptographic
Appliances Incorporated. Since the project was released into open source, it
has a home page and a project environment where development, 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 email@example.com.
Home Page: http://www.distcache.org
|1.4.5 ||NAL_SELECTOR_NEW (2) ||2004.03.23 |
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