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MSTOHZ(9) NetBSD Kernel Developer's Manual MSTOHZ(9)
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Maintained for NetBSD
by Kimmo Suominen.
Based on man-cgi by Panagiotis Christias.
mstohz, hztoms -- convert between milliseconds and system clock ticks
mstohz(unsigned int ms);
hztoms(unsigned int hz);
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 millisec-
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.
The return value is either the number of clock ticks or milliseconds for
the specified value.
param(3), callout(9), tvtohz(9)
Neither mstohz() nor hztoms() make use of expensive 64-bit integer arith-
metic. The result from mstohz() will be rounded down to one second if
the parameter is larger than 131072 milliseconds.
NetBSD 9.99 September 28, 2019 NetBSD 9.99