HP-UX Reference (11i v3 07/02) - 2 System Calls (vol 5)

ualarm(2) ualarm(2)

NAME

ualarm - set the interval timer

SYNOPSIS

#include <unistd.h>

useconds_t ualarm(useconds_t useconds, useconds_t interval);

DESCRIPTION

The ualarm() function causes the SIGALRM signal to be generated for the calling process after the

number of real-time microseconds speciﬁed by the useconds argument has elapsed. When the interval argu-

ment is non-zero, repeated timeout notiﬁcation occurs with a period in microseconds speciﬁed by the inter-

val argument. If the notiﬁcation signal,

SIGALRM, is not caught or ignored, the calling process is ter-

minated.

Implementations may place limitations on the granularity of timer values. For each interval timer, if the

requested timer value requires a ﬁner granularity than the implementation supports, the actual timer

value will be rounded up to the next supported value.

Interactions between

ualarm() and either alarm() or sleep() are unspeciﬁed.

RETURN VALUE

The ualarm() function returns the number of microseconds remaining from the previous ualarm()

call. If no timeouts are pending or if ualarm() has not previously been called, ualarm() returns 0.

ERRORS

No errors are deﬁned.

APPLICATION USAGE

The

ualarm() function is a simpliﬁed interface to setitimer(), and uses the ITIMER_REAL

inter-

val timer.