netbsd man page for mstohz

MSTOHZ(9)						   BSD Kernel Developer's Manual						 MSTOHZ(9)

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-over-
     flow 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.

BSD
								 October 20, 2011							       BSD