UALARM(3) Linux Programmer's Manual UALARM(3)NAMEualarm - schedule signal after given number of microseconds
SYNOPSIS
/* BSD version */
#include <unistd.h>
unsigned int ualarm(unsigned int usecs, unsigned int interval);
/* SUSv2 version */
#define _XOPEN_SOURCE 500
#include <unistd.h>
useconds_t ualarm(useconds_t usecs, useconds_t interval);
DESCRIPTION
The ualarm() function causes the signal SIGALRM to be sent to the
invoking process after (not less than) usecs microseconds. The delay
may be lengthened slightly by any system activity or by the time spent
processing the call or by the granularity of system timers.
Unless caught or ignored, this signal will terminate the process.
If the interval argument is non-zero, further SIGALRM signals will be
sent every interval microseconds after the first.
RETURN VALUE
This function returns the number of microseconds remaining from the
previous call, or 0 when no alarm is pending.
ERRORS
EINTR Interrupted by a signal.
EINVAL usecs or interval is not smaller than 1000000. (On systems
where that is considered an error.)
CONFORMING TO
4.3BSD, POSIX.1-2001. 4.3BSD, SUSv2 and POSIX do not define any
errors.
NOTES
The type useconds_t is an unsigned integer type capable of holding
integers in the range [0,1000000]. This type is defined by
<sys/types.h> included by <unistd.h> but glibc defines it only when
_XOPEN_SOURCE has a value not less than 500, or both _XOPEN_SOURCE and
_XOPEN_SOURCE_EXTENDED are defined. Programs will be more portable if
they never mention this type explicitly.
The interaction of this function with other timer functions such as
alarm(), sleep(), nanosleep(), setitimer(), timer_create(),
timer_delete(), timer_getoverrun(), timer_gettime(), timer_settime(),
usleep() is unspecified.
This function is obsolete. Use nanosleep(2) or setitimer(2) instead.
SEE ALSOalarm(2), getitimer(2), nanosleep(2), select(2), setitimer(2),
usleep(3), feature_test_macros(7)
2003-07-24 UALARM(3)
