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NAME | C SYNOPSIS | DESCRIPTION | NOTES | COMPATIBILITY | SEE ALSO | COLOPHON |
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PMTIMESPECNOW(3) Library Functions Manual PMTIMESPECNOW(3)
pmtimespecNow, pmtimespecInc, pmtimespecDec, pmtimespecAdd,
pmtimespecSub, pmtimespecToReal, pmtimespecFromReal,
pmtimespecTotimeval, pmtimespecPrint, pmtimespecPrintInterval -
helper routines for time stored as a struct timespec
#include <pcp/pmapi.h>
void pmtimespecNow(struct timespec *tp);
void pmtimespecInc(struct timespec *ap, const struct timespec
*bp);
void pmtimespecDec(struct timespec *ap, const struct timespec
*bp);
double pmtimespecAdd(const struct timespec *ap,
const struct timespec *bp);
double pmtimespecSub(const struct timespec *ap,
const struct timespec *bp);
double pmtimespecToReal(const struct timespec *tp);
void pmtimespecFromReal(double secs, struct timespec *tp);
void pmtimespecTotimeval(struct timespec *tsp, struct timeval
*tvp);
void pmtimespecPrint(FILE *f, const struct timespec *tp);
void pmtimespecPrintInterval(FILE *f, const struct timespec *tp);
cc ... -lpcp
pmtimespecNow is a platform-independent method that returns the
current system time since the Epoch in tp.
pmtimespecInc adds the time in ap to the time in bp and stores the
result in ap. Similarly pmtimespecDec subtracts the time in bp
from the time in ap and stores the result in ap.
pmtimespecAdd (and pmtimespecSub) add (and subtract) times and re‐
turn the result as a double value. The time in the ap argument is
not changed.
pmtimespecToReal converts the time in tp to an equivalent double
value. pmtimespecFromReal provides the reverse conversion, taking
the time in secs and returning the equivalent time in tp.
pmtimespecTotimeval converts the struct timespec tsp into an
equivalent struct timeval tvp (modulo nanosecond to microsecond
truncation).
For pmtimespecAdd, pmtimespecSub, pmtimespecToReal and pmtime‐
specFromReal there is an issue of numerical precision. If the
double result or operand has more than 6 decimal digits of preci‐
sion in the seconds part of the value, then the fractional value
is converted to microseconds before arithmetic computations, so
the nanoseconds field is only accurate to 6 decimal digits in this
case.
pmtimespecPrint prints the timestamp from tp on the stream f in
the local time (as returned by pmLocaltime(3)) in the format
HH:MM:SS.XXXXXXXXX.
pmtimespecPrintInterval prints the interval from tp on the stream
f in a minimalist format [[HHh]MMm]SS[.XXXXXXXXX]s where the
hours, minutes and nanoseconds are only reported if they are non-
zero, and any trailing zeroes in the nanoseconds are omitted. For
example if tp->tv_sec was 75 and tp->tv_nsec was 51000000 then the
output would be 1h15.51s.
For variants of these interfaces using microsecond precision and
the timeval structure, refer to pmtimevalNow(3).
Prior to PCP 7.0 the routine pmtimespecPrint was called pmPrint‐
HighResStamp. To support PMAPI transition, the old routine can
still be used if applications are recompiled with -DPMAPI_VER‐
SION=2.
pmPrintHighResStamp is now deprecated and compile-time support for
this routine name will be removed in a future release.
PMAPI(3), pmLocaltime(3) and pmtimevalNow(3).
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-08-11.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
Performance Co-Pilot PCP PMTIMESPECNOW(3)
Pages that refer to this page: pmtimeval(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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