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eggerteggert
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timeout: don’t sleep less than requested
Also, change sleep and tail to not sleep less than requested. * bootstrap.conf (gnulib_modules): Add dtimespec-bound. * gl/lib/dtimespec-bound.c, gl/lib/dtimespec-bound.h: * gl/modules/dtimespec-bound: New files. * src/sleep.c, src/tail.c, src/timeout.c: Include dtimespec-bound.h. * src/sleep.c, src/tail.c: Don’t include xstrtod.h. * src/sleep.c (apply_suffix, main): * src/tail.c (parse_options): * src/timeout.c (apply_time_suffix): Don’t sleep less than the true number of seconds. * src/timeout.c: Don’t include ctype.h. (is_negative): Remove; no longer needed. (parse_duration): Use a slightly looser bound on the timeout, one that doesn’t need -lm on GNU/Linux. Clear errno before calling cl_strtod.
1 parent 0311d45 commit cb7c210

8 files changed

Lines changed: 129 additions & 32 deletions

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‎NEWS‎

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@@ -27,6 +27,10 @@ GNU coreutils NEWS -*- outline -*-
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For example `timeout 1e-5000 sleep inf` would never timeout.
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[bug introduced with timeout in coreutils-7.0]
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sleep, tail, and timeout would sometimes sleep for slightly less
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time than requested.
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[bug introduced in coreutils-5.0]
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'who -m' now outputs entries for remote logins. Previously login
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entries prefixed with the service (like "sshd") were not matched.
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[bug introduced in coreutils-9.4]

‎bootstrap.conf‎

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@@ -78,6 +78,7 @@ gnulib_modules="
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dirfd
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dirname
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do-release-commit-and-tag
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dtimespec-bound
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dtoastr
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dup2
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endian

‎gl/lib/dtimespec-bound.c‎

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#include <config.h>
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#define DTIMESPEC_BOUND_INLINE _GL_EXTERN_INLINE
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#include "dtimespec-bound.h"

‎gl/lib/dtimespec-bound.h‎

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/* Compute a timespec-related bound for floating point.
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Copyright 2025 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Paul Eggert */
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#ifndef DTIMESPEC_BOUND_H
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#define DTIMESPEC_BOUND_H 1
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/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE. */
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#if !_GL_CONFIG_H_INCLUDED
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#error "Please include config.h first."
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#endif
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#include <errno.h>
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#include <float.h>
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#include <math.h>
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_GL_INLINE_HEADER_BEGIN
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#ifndef DTIMESPEC_BOUND_INLINE
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# define DTIMESPEC_BOUND_INLINE _GL_INLINE
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#endif
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/* If C is positive and finite, return the least floating point value
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greater than C. However, if 0 < C < (2 * DBL_TRUE_MIN) / (DBL_EPSILON**2),
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return a positive value less than 1e-9.
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If C is +0.0, return a positive value < 1e-9 if ERR == ERANGE, C otherwise.
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If C is +Inf, return C.
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If C is negative, return -timespec_roundup(-C).
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If C is a NaN, return a NaN.
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Assume round-to-even.
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This function can be useful if some floating point operation
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rounded to C but we want a nearby bound on the true value, where
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the bound can be converted to struct timespec. If the operation
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underflowed to zero, ERR should be ERANGE a la strtod. */
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DTIMESPEC_BOUND_INLINE double
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dtimespec_bound (double c, int err)
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{
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/* Do not use copysign or nextafter, as they link to -lm in GNU/Linux. */
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/* Use DBL_TRUE_MIN for the special case of underflowing to zero;
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any positive value less than 1e-9 will do. */
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if (err == ERANGE && c == 0)
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return signbit (c) ? -DBL_TRUE_MIN : DBL_TRUE_MIN;
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/* This is the first part of Algorithm 2 of:
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Rump SM, Zimmermann P, Boldo S, Melquiond G.
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Computing predecessor and successor in rounding to nearest.
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BIT Numer Math. 2009;49(419-431).
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<https://doi.org/10.1007/s10543-009-0218-z>
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The rest of Algorithm 2 is not needed because numbers less than
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the predecessor of 1e-9 merely need to stay less than 1e-9. */
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double phi = DBL_EPSILON / 2 * (1 + DBL_EPSILON);
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return c + phi * c;
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}
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_GL_INLINE_HEADER_END
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#endif

‎gl/modules/dtimespec-bound‎

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Description:
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Adjust a double to provide a timespec bound.
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Files:
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lib/dtimespec-bound.c
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lib/dtimespec-bound.h
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Depends-on:
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float-h
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signbit
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configure.ac:
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Makefile.am:
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lib_SOURCES += dtimespec-bound.c
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Include:
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"dtimespec-bound.h"
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License:
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GPL
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Maintainer:
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all

‎src/sleep.c‎

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@@ -20,10 +20,10 @@
2020

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#include "system.h"
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#include "cl-strtod.h"
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#include "dtimespec-bound.h"
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#include "long-options.h"
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#include "quote.h"
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#include "xnanosleep.h"
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#include "xstrtod.h"
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/* The official name of this program (e.g., no 'g' prefix). */
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#define PROGRAM_NAME "sleep"
@@ -85,7 +85,7 @@ apply_suffix (double *x, char suffix_char)
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return false;
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}
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*x *= multiplier;
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*x = dtimespec_bound (*x * multiplier, 0);
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return true;
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}
@@ -116,9 +116,11 @@ main (int argc, char **argv)
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for (int i = optind; i < argc; i++)
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{
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double s;
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char const *p;
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if (! (xstrtod (argv[i], &p, &s, cl_strtod) || errno == ERANGE)
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char *p;
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errno = 0;
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double duration = cl_strtod (argv[i], &p);
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double s = dtimespec_bound (duration, errno);
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if (argv[i] == p
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/* Nonnegative interval. */
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|| ! (0 <= s)
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/* No extra chars after the number and an optional s,m,h,d char. */
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ok = false;
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}
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seconds += s;
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seconds = dtimespec_bound (seconds + s, 0);
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}
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if (!ok)

‎src/tail.c‎

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@@ -35,6 +35,7 @@
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#include "assure.h"
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#include "c-ctype.h"
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#include "cl-strtod.h"
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#include "dtimespec-bound.h"
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#include "fcntl--.h"
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#include "iopoll.h"
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#include "isapipe.h"
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#include "xdectoint.h"
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#include "xnanosleep.h"
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#include "xstrtol.h"
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#include "xstrtod.h"
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#if HAVE_INOTIFY
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# include "hash.h"
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case 's':
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{
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double s;
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if (! (xstrtod (optarg, nullptr, &s, cl_strtod) && 0 <= s))
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char *ep;
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errno = 0;
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double s = cl_strtod (optarg, &ep);
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if (optarg == ep || *ep || ! (0 <= s))
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error (EXIT_FAILURE, 0,
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_("invalid number of seconds: %s"), quote (optarg));
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*sleep_interval = s;
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*sleep_interval = dtimespec_bound (s, errno);
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}
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break;
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‎src/timeout.c‎

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@@ -45,7 +45,6 @@
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Written by Pádraig Brady. */
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#include <config.h>
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#include <ctype.h>
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#include <getopt.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include "system.h"
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#include "cl-strtod.h"
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#include "dtimespec-bound.h"
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#include "sig2str.h"
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#include "operand2sig.h"
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#include "quote.h"
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return false;
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}
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*x *= multiplier;
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*x = dtimespec_bound (*x * multiplier, 0);
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return true;
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}
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ATTRIBUTE_PURE static bool
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is_negative (char const *num)
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{
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while (*num && isspace (to_uchar (*num)))
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num++;
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return *num == '-';
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}
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static double
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parse_duration (char const *str)
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{
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char *ep;
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errno = 0;
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double duration = cl_strtod (str, &ep);
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double s = dtimespec_bound (duration, errno);
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if (ep == str
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/* Nonnegative interval. */
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|| ! (0 <= duration)
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/* The interval did not underflow to -0. */
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|| (errno == ERANGE && is_negative (str))
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|| ! (0 <= s)
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/* No extra chars after the number and an optional s,m,h,d char. */
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|| (*ep && *(ep + 1))
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/* Check any suffix char and update timeout based on the suffix. */
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|| !apply_time_suffix (&duration, *ep))
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|| !apply_time_suffix (&s, *ep))
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{
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error (0, 0, _("invalid time interval %s"), quote (str));
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usage (EXIT_CANCELED);
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}
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/* Do not let the duration underflow to 0, as 0 disables the timeout.
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Use 2**-30 instead of 0; settimeout will round it up to 1 ns,
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whereas 1e-9 might double-round to 2 ns. */
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if (duration == 0 && errno == ERANGE)
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duration = 9.313225746154785e-10;
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return duration;
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return s;
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}
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static void

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