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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
commit | 399644e47874bff147afb19c89228901ac39340e (patch) | |
tree | 1c4c0b733f4c16b5783b41bebb19194a9ef62ad1 /man3/ualarm.3 | |
parent | Initial commit. (diff) | |
download | manpages-ac8a94b90d5cf454cd6648203aaf1c44d642788f.tar.xz manpages-ac8a94b90d5cf454cd6648203aaf1c44d642788f.zip |
Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man3/ualarm.3')
-rw-r--r-- | man3/ualarm.3 | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/man3/ualarm.3 b/man3/ualarm.3 new file mode 100644 index 0000000..55ca2d7 --- /dev/null +++ b/man3/ualarm.3 @@ -0,0 +1,141 @@ +'\" t +.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.TH ualarm 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +ualarm \- schedule signal after given number of microseconds +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B "#include <unistd.h>" +.PP +.BI "useconds_t ualarm(useconds_t " usecs ", useconds_t " interval ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR ualarm (): +.nf + Since glibc 2.12: + (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200809L) + || /* glibc >= 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE + Before glibc 2.12: + _BSD_SOURCE || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED +.fi +.SH DESCRIPTION +The +.BR ualarm () +function causes the signal +.B SIGALRM +to be sent to the invoking process after (not less than) +.I 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. +.PP +Unless caught or ignored, the +.B SIGALRM +signal will terminate the process. +.PP +If the +.I interval +argument is nonzero, further +.B SIGALRM +signals will be sent every +.I interval +microseconds after the first. +.SH RETURN VALUE +This function returns the number of microseconds remaining for +any alarm that was previously set, or 0 if no alarm was pending. +.SH ERRORS +.TP +.B EINTR +Interrupted by a signal; see +.BR signal (7). +.TP +.B EINVAL +\fIusecs\fP or \fIinterval\fP is not smaller than 1000000. +(On systems where that is considered an error.) +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR ualarm () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +None. +.SH HISTORY +4.3BSD, POSIX.1-2001. +POSIX.1-2001 marks it as obsolete. +Removed in POSIX.1-2008. +.PP +4.3BSD, SUSv2, and POSIX do not define any errors. +.PP +POSIX.1-2001 does not specify what happens if the +.I usecs +argument is 0. +.\" This case is not documented in HP-US, Solar, FreeBSD, NetBSD, or OpenBSD! +On Linux (and probably most other systems), +the effect is to cancel any pending alarm. +.PP +The type +.I useconds_t +is an unsigned integer type capable of holding integers +in the range [0,1000000]. +On the original BSD implementation, and in glibc before glibc 2.1, +the arguments to +.BR ualarm () +were instead typed as +.IR "unsigned int" . +Programs will be more portable if they never mention +.I useconds_t +explicitly. +.PP +The interaction of this function with +other timer functions such as +.BR alarm (2), +.BR sleep (3), +.BR nanosleep (2), +.BR setitimer (2), +.BR timer_create (2), +.BR timer_delete (2), +.BR timer_getoverrun (2), +.BR timer_gettime (2), +.BR timer_settime (2), +.BR usleep (3) +is unspecified. +.PP +This function is obsolete. +Use +.BR setitimer (2) +or POSIX interval timers +.RB ( timer_create (2), +etc.) +instead. +.SH SEE ALSO +.BR alarm (2), +.BR getitimer (2), +.BR nanosleep (2), +.BR select (2), +.BR setitimer (2), +.BR usleep (3), +.BR time (7) |