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Diffstat (limited to 'doc/libstddjb/iopause.html')
| -rw-r--r-- | doc/libstddjb/iopause.html | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/doc/libstddjb/iopause.html b/doc/libstddjb/iopause.html index ff8727c..bcefb91 100644 --- a/doc/libstddjb/iopause.html +++ b/doc/libstddjb/iopause.html @@ -29,12 +29,12 @@ and implemented in the <tt>libskarnet.a</tt> or <tt>libskarnet.so</tt> library. <p> <tt>iopause</tt> is the skalibs API for event loop selection. It's a -wrapper around the system's +wrapper around the system's <tt>ppoll()</tt> or <a href="http://www.opengroup.org/onlinepubs/9699919799/functions/poll.html">poll()</a> (if available) or <a href="http://www.opengroup.org/onlinepubs/9699919799/functions/select.html">select()</a> -(if <tt>poll()</tt> is unavailable) function. It -works around some system-dependent quirks; also it works with +(if neither <tt>ppoll()</tt> n or <tt>poll()</tt> is available) function. + It works around some system-dependent quirks; also it works with <em>absolute dates</em> instead of timeouts. This is a good thing: see below. </p> @@ -175,22 +175,23 @@ it is recommended to use this function instead of the lower-level <h3> Underlying implementations </h3> <p> - <tt>iopause</tt> is an alias to either <tt>iopause_poll</tt> or -or <tt>iopause_select</tt>. By default, it is aliased to <tt>iopause_poll</tt>; to -alias it to <tt>iopause_select</tt> instead, configure skalibs with the -<tt>--enable-iopause-select</tt> option. + <tt>iopause</tt> is an alias to one of <tt>iopause_ppoll</tt>, <tt>iopause_poll</tt> or +<tt>iopause_select</tt>. It is always aliased to <tt>iopause_ppoll</tt> if +the <tt>ppoll()</tt> function is available on the system; else, it's aliased to +<tt>iopause_poll</tt> by default, and users can alias it to <tt>iopause_select</tt> +instead if they configure skalibs with the <tt>--enable-iopause-select</tt> option. </p> <p> -Both <tt>iopause_poll</tt> and <tt>iopause_select</tt> are implemented on top of the -<a href="http://man7.org/linux/man-pages/man2/ppoll.2.html">ppoll()</a> system call -if it is available; but if it is not, then <tt>iopause_poll</tt> defaults to -<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/poll.html">poll()</a>, -which has a more comfortable API than +<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/poll.html">poll()</a> +has a more comfortable API than <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/select.html">select()</a>, -but a maximum precision of 1 millisecond which might not be enough for some applications; whereas -<tt>iopause_select</tt> defaults to select(), which incurs some CPU overhead for the -API conversion, but has a 1 microsecond precision. +but its maximum precision is 1 millisecond, which might not be enough for some applications; +using <tt>select()</tt> instead incurs some CPU overhead for the API conversion, but has a +1 microsecond precision. +<a href="http://man7.org/linux/man-pages/man2/poll.2.html">ppoll()</a> gets the best of +both worlds with the same interface model as <tt>poll()</tt> and a 1 nanosecond precision, +which is why skalibs always uses it when available. </p> </body> |