drv_hztousec(D3) drv_hztousec(D3)
NAME
drv_hztousec - convert clock ticks to microseconds
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
clock_t drv_hztousec(clock_t ticks);
Arguments
ticks The number of clock ticks to convert to equivalent
microseconds.
DESCRIPTION
drv_hztousec converts the length of time expressed by ticks,
which is in units of clock ticks, into units of microseconds.
Return Values
drv_hztousec returns the number of microseconds equivalent to
the ticks argument. No error value is returned. If the
microsecond equivalent to ticks is too large to be represented
as a clock_t, then the maximum clock_t value is returned.
USAGE
Several functions either take time values expressed in clock
ticks as arguments [timeout(D3), timeout(D3), delay(D3)] or
return time values expressed in clock ticks [drv_getparm(D3)].
The length of a clock tick can vary across different
implementations, and therefore drivers should not include any
hard-coded assumptions about the length of a tick.
drv_hztousec and the complementary function drv_usectohz(D3)
can be used, as necessary, to convert between clock ticks and
microseconds.
Note that the time value returned by drv_getparm with an LBOLT
argument will frequently be too large to represent in
microseconds as a clock_t. When using drv_getparm together
with drv_hztousec to time operations, drivers can help avoid
overflow by converting the difference between return values
from successive calls to drv_getparm instead of trying to
convert the return values themselves.
Level
Initialization, Base or Interrupt.
Copyright 1994 Novell, Inc. Page 1
drv_hztousec(D3) drv_hztousec(D3)
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks
may be held across calls to this function.
REFERENCES
delay(D3), drv_getparm(D3), drv_usectohz(D3), itimeout(D3)
timeout(D3)
NOTICES
Portability
All processors
Applicability
ddi: 1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp
Copyright 1994 Novell, Inc. Page 2