xref: /inferno-os/man/10/seconds (revision 46439007cf417cbd9ac8049bb4122c890097a0fa)
SECONDS 10.2
NAME
seconds, ticks, HZ, MS2HZ, MS2TK, TK2MS, TK2SEC - kernel times and time conversions
SYNOPSIS
long seconds(void)

ulong ticks(void)

.EX #define HZ ... #define MS2HZ(t) ... #define TK2SEC(t) ... #define TK2MS(t) ... #define MS2TK(m) ...

DESCRIPTION
Seconds returns the system's idea of the current time as the number of seconds since the start of the epoch (00:00:00 GMT, January 1, 1970).

Ticks returns the number of system-dependent clock ticks since system boot.

The system clock frequency is platform-dependent. Several symbolic constants and macro functions are defined by the file mem.h to convert between different time units: .TF TK2SEC(t)

HZ The number of clock ticks per second.

MS2HZ Milliseconds per clock tick.

TK2SEC( t ) Convert t clock ticks to seconds and return the result (truncating not rounding).

TK2MS( t ) Convert t clock ticks to milliseconds and return the result.

MS2TK( m ) Convert m milliseconds to clock ticks and return the result (truncating).

The functions are often used to calculate delays for timing functions, for instance:

.EX if(atactlrwait(dp->cp, DHmagic, 0, MS2TK(100))){ ... }