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