Section: Linux Programmer's Manual (3)
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ualarm - schedule signal after given number of microseconds
/* BSD version */
unsigned int ualarm(unsigned int usecs, unsigned int interval);
/* SUSv2 version */
#define _XOPEN_SOURCE 500
useconds_t ualarm(useconds_t usecs, useconds_t interval);
The ualarm() function causes the signal SIGALRM to be sent
to the invoking process after (not less than)
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.
argument is non-zero, further SIGALRM signals will be sent every
microseconds after the first.
This function returns the number of microseconds remaining from
the previous call, or 0 when no alarm is pending.
Interrupted by a signal.
usecs or interval is not smaller than 1000000.
(On systems where that is considered an error.)
4.3BSD, SUSv2 and POSIX do not define any errors.
is an unsigned integer type capable of holding integers
in the range [0,1000000].
This type is defined by
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
This function is obsolete. Use
- RETURN VALUE
- CONFORMING TO
- SEE ALSO
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