opensolaris man page for drv_hztousec

drv_hztousec(9F)					   Kernel Functions for Drivers 					  drv_hztousec(9F)

NAME
       drv_hztousec - convert clock ticks to microseconds

SYNOPSIS
       #include <sys/types.h>
       #include <sys/ddi.h>

       clock_t drv_hztousec(clock_t hertz);

INTERFACE LEVEL
       Architecture independent level 1 (DDI/DKI).

PARAMETERS
       hertz	The number of clock ticks to convert.

DESCRIPTION
       The drv_hztousec() function converts into microseconds the time expressed by hertz, which is in system clock ticks.

       The kernel variable lbolt, whose value should be retrieved by calling ddi_get_lbolt(9F), is the length of time the system has been up since
       boot and is expressed in clock ticks. Drivers often use the value of lbolt before and after an I/O request to measure the amount of time it
       took  the device to process the request. The drv_hztousec() function can be used by the driver to convert the reading from clock ticks to a
       known unit of time.

RETURN VALUES
       The number of microseconds equivalent to the hertz parameter. No error value is returned. If the microsecond equivalent	to  hertz  is  too
       large to be represented as a clock_t, then the maximum clock_t value will be returned.

CONTEXT
       The drv_hztousec() function can be called from user, interrupt, or kernel context.

SEE ALSO
       ddi_get_lbolt(9F), drv_usectohz(9F), drv_usecwait(9F)

       Writing Device Drivers

SunOS 5.11							    16 Jan 2006 						  drv_hztousec(9F)