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

       drv_hztousec() 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. drv_hztousec() 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

       drv_hztousec() can be called from user or interrupt context.

SEE ALSO

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

       Writing Device Drivers

SunOS 5.10							    12 Nov 1992 						  drv_hztousec(9F)