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Command: ppsratecheck | Section: 9 | Source: FreeBSD | File: ppsratecheck.9.gz
RATECHECK(9) FreeBSD Kernel Developer's Manual RATECHECK(9)
NAME
ratecheck, ppsratecheck - event rate limiting
SYNOPSIS
#include <sys/time.h>
int
ratecheck(struct timeval *lasttime, const struct timeval *mininterval);
int
ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps);
DESCRIPTION
The ratecheck and ppsratecheck functions facilitate rate-limiting of
arbitrary events. The former enforces a minimum interval between events
while the latter enforces a maximum number of events per second.
The ratecheck function compares the current time to the value pointed to
by lasttime. If the difference is equal to or greater than mininterval,
it returns a non-zero value and updates lasttime to the current time.
Otherwise, it returns zero.
The ppsratecheck function first compares the current time to lasttime.
If at least a full second has passed, the value pointed to by the curpps
argument is reset to 1 and lasttime is updated to the current time.
Otherwise, curpps is incremented and lasttime is left untouched. In
either case, ppsratecheck returns a non-zero value if and only if the
updated curpps is less than or equal to maxpps or maxpps is negative.
SEE ALSO
counter(9)
HISTORY
The ratecheck and ppsratecheck functions first appeared in FreeBSD 5.1.
FreeBSD 14.1-RELEASE-p8 March 11, 2022 FreeBSD 14.1-RELEASE-p8