Updated: 2022/Sep/29

Please read Privacy Policy. It's for your privacy.

MSTOHZ(9)                  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.

NetBSD 10.99                  September 28, 2019                  NetBSD 10.99