drv_hztousec(D3)drv_hztousec(D3)NAMEdrv_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.
DESCRIPTIONdrv_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 [itimeout(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.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function.
REFERENCESdelay(D3), drv_getparm(D3), drv_usectohz(D3), itimeout(D3)
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