DELAY(9) BSD Kernel Developer's Manual DELAY(9)
NAME
delay, DELAY -- microsecond delay
SYNOPSIS
#include <machine/param.h>
void
delay(unsigned int us);
void
DELAY(unsigned int us);
DESCRIPTION
Wait approximately us microseconds.
The delay is implemented as a machine loop, preventing events other than interrupt handlers for unmasked interrupts to run. DELAY() is reen-
trant (doesn't modify any global kernel or machine state) and is safe to use in interrupt or process context.
For long delays, condition variables should be considered, however they can only be used from process context and their resolution is limited
by the system clock frequency.
SEE ALSO
condvar(9), hz(9), kpause(9)
BSD
July 20, 2011 BSD
