ADJTIME(2) — SYSTEM CALLS

NAME

adjtime − ajdust time

SYNOPSIS

#include <sys/time.h>

adjtime(tp, otp)
struct timeval ∗tp, ∗otp;

DESCRIPTION

Adjtime adjusts the system’s notion of the current time. The time is adjusted by the amount of time in ∗tp. The old adjustment value is returned in ∗otp.

The adjustment is effected by speeding up or slowing down the system’s clock by a fixed percentage, currently 10%.

The structures pointed to by tp and otp are defined in <sys/time.h> as:

struct timeval {
u_longtv_sec;/∗ seconds since Jan. 1, 1970 ∗/
longtv_usec;/∗ and microseconds ∗/
};

If otp is a zero pointer, the corresponding information will not be returned.

Only the super-user may adjust the time of day.

The adjustment value will be silently rounded to the resolution of the system clock.

RETURN

A 0 return value indicates that the call succeeded. A −1 return value indicates an error occurred, and in this case an error code is stored into the global variable errno.

ERRORS

The following error codes may be set in errno:

[EFAULT] An argument address referenced invalid memory.

[EPERM] A user other than the super-user attempted to set the time.

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