1 .\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)
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23 .TH UALARM 3 2007-07-26 "" "Linux Programmer's Manual"
25 ualarm \- schedule signal after given number of microseconds
28 .B "#include <unistd.h>"
30 .BI "useconds_t ualarm(useconds_t " usecs ", useconds_t " interval );
34 Feature Test Macro Requirements for glibc (see
35 .BR feature_test_macros (7)):
39 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500
43 function causes the signal
45 to be sent to the invoking process after (not less than)
48 The delay may be lengthened slightly by any system activity
49 or by the time spent processing the call or by the
50 granularity of system timers.
52 Unless caught or ignored, the
54 signal will terminate the process.
58 argument is non-zero, further
60 signals will be sent every
62 microseconds after the first.
64 This function returns the number of microseconds remaining for
65 any alarm that was previously set, or 0 if no alarm was pending.
69 Interrupted by a signal.
72 \fIusecs\fP or \fIinterval\fP is not smaller than 1000000.
73 (On systems where that is considered an error.)
79 4.3BSD, SUSv2, and POSIX do not define any errors.
83 is an unsigned integer type capable of holding integers
84 in the range [0,1000000].
85 On the original BSD implementation, and in glibc before version 2.1,
90 Programs will be more portable if they never mention
94 The interaction of this function with
95 other timer functions such as
100 .BR timer_create (3),
101 .BR timer_delete (3),
102 .BR timer_getoverrun (3),
103 .BR timer_gettime (3),
104 .BR timer_settime (3),
108 This function is obsolete.
111 or POSIX interval timers
112 .RB ( timer_create (3),