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Command: hztoms | Section: 9 | Source: NetBSD | File: hztoms.9
MSTOHZ(9) FreeBSD Kernel Developer's Manual MSTOHZ(9)
NAME
mstohz, hztoms - convert between milliseconds and system clock ticks
SYNOPSIS
#include <sys/param.h>
unsigned int
mstohz(unsigned int ms);
unsigned int
hztoms(unsigned int hz);
DESCRIPTION
The mstohz() macro can be used to convert time in milliseconds to system
clock ticks, as used by the callout(9) facility, in an integer-overflow
safe way. Conversely, hztoms() converts system clock ticks to
milliseconds.
These macros are defined in the <sys/param.h> header. Individual ports
can have a processor-specific, more efficient version implemented in
their <machine/param.h> header as a define.
RETURN VALUES
The return value is either the number of clock ticks or milliseconds for
the specified value.
SEE ALSO
param(3), callout(9), tvtohz(9)
BUGS
Neither mstohz() nor hztoms() make use of expensive 64-bit integer
arithmetic. The result from mstohz() will be rounded down to one second
if the parameter is larger than 131072 milliseconds.
FreeBSD 14.1-RELEASE-p8 September 28, 2019 FreeBSD 14.1-RELEASE-p8