1 .\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)
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23 .TH UALARM 3 2003-07-24 "" "Linux Programmer's Manual"
25 ualarm \- schedule signal after given number of microseconds
28 .B "#define _XOPEN_SOURCE 500 /* Or: #define _BSD_SOURCE */
29 .B "#include <unistd.h>"
31 .BI "useconds_t ualarm(useconds_t " usecs ", useconds_t " interval );
34 The \fBualarm\fP() function causes the signal SIGALRM to be sent
35 to the invoking process after (not less than)
38 The delay may be lengthened slightly by any system activity
39 or by the time spent processing the call or by the
40 granularity of system timers.
42 Unless caught or ignored, the SIGALRM signal will terminate the process.
46 argument is non-zero, further SIGALRM signals will be sent every
48 microseconds after the first.
50 This function returns the number of microseconds remaining for
51 any alarm that was previously set, or 0 if no alarm was pending.
55 Interrupted by a signal.
58 \fIusecs\fP or \fIinterval\fP is not smaller than 1000000.
59 (On systems where that is considered an error.)
65 4.3BSD, SUSv2, and POSIX do not define any errors.
69 is an unsigned integer type capable of holding integers
70 in the range [0,1000000].
71 On the original BSD implementation, and in glibc before version 2.1,
76 Programs will be more portable if they never mention
80 The interaction of this function with
81 other timer functions such as
88 .BR timer_getoverrun (),
94 This function is obsolete. Use
96 or POSIX interval timers
97 .RB ( timer_create (),
107 .BR feature_test_macros (7),