NAME
mstohz,
hztoms —
convert between milliseconds and system clock ticks
SYNOPSIS
#include <sys/param.h>
int
mstohz(
int
ms);
int
hztoms(
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.