taia_now(3) Library Functions Manual taia_now(3)NAME
taia_now - get current time
SYNTAX
#include <taia.h>
extern int taia_now(struct taia* t);
DESCRIPTION
taia_now puts the current time into t. More precisely: tai_now puts into t its best guess as to the TAI64NA label for the 1-attosecond
interval that contains the current time.
This implementation of taia_now assumes that the time_t returned from the time function represents the number of TAI seconds since
1970-01-01 00:00:10 TAI. This matches the convention used by the Olson tz library in ``right'' mode.
Beware that many clocks are not set accurately, and even the best scientific clocks are nowhere near 1-attosecond accuracy; however, an
inaccurate clock may still produce reasonably accurate time differences.
SEE ALSO tai_now(3)taia_now(3)
Check Out this Related Man Page
iopause(3) Library Functions Manual iopause(3)NAME
iopause - check for file descriptor readability or writability
SYNTAX
#include <iopause.h>
int iopause(iopause_fd** x,unsigned int len,
struct taia deadline,struct taia stamp);
DESCRIPTION
iopause checks for file descriptor readability or writability as specified by x[0].fd, x[0].events, x[1].fd, x[1].events, ..., x[len-1].fd,
x[len-1].events. If x[i].events includes the bit IOPAUSE_READ, iopause checks for readability of the descriptor x[i].fd; if x[i].events
includes the bit IOPAUSE_WRITE, iopause checks for writability of the descriptor x[i].fd; other bits in x[i].events have undefined effects.
iopause sets the IOPAUSE_READ bit in x[i].revents if it finds that x[i].fd is readable, and it sets the IOPAUSE_WRITE bit in x[i].revents
if it finds that x[i].fd is writable. Beware that readability and writability may be destroyed at any moment by other processes with access
to the same ofile that x[i].fd refers to.
If there is no readability or writability to report, iopause waits until deadline for something to happen. iopause will return before dead-
line if a descriptor becomes readable or writable, or an interrupting signal arrives, or some system-defined amount of time passes. iopause
sets revents in any case.
You must put a current timestamp into stamp before calling iopause.
IMPLEMENTATION NOTES
The current implementation of iopause uses the poll function if that is available. On some systems, poll needs to dynamically allocate ker-
nel memory; when not much memory is available, iopause will return immediately, and will report (often incorrectly) that no descriptors are
readable or writable. This is a kernel bug, and I encourage vendors to fix it.
If poll is not available, iopause uses the select function. This function cannot see descriptor numbers past a system-defined limit, typi-
cally 256 or 1024; iopause will artificially pretend that those descriptors are never readable or writable.
Future implementations of iopause may work around these problems on some systems, at the expense of chewing up all available CPU time.
Both poll and select use relative timeouts rather than absolute deadlines. Some kernels round the timeout down to a multiple of 10 mil-
liseconds; this can burn quite a bit of CPU time as the deadline approaches. iopause compensates for this by adding 20 milliseconds to the
timeout.
SEE ALSO select(2), poll(3), taia_now(3)iopause(3)