Update: After finishing my coffee, I realize that it's normal behavior: it's just an artifact of adding a number slightly larger than an integer (epsilon_1) to another number slightly less than another integer (epsilon_2), where epsilon_1 happens to be greater than epsilon_2. As an example: 5.99 + 1.02 => 7.01
I gave it a few tries and was able to reproduce it:
$ perl -MTime::HiRes=time -le 'while () { $a=time; print $a, " ", $a-$
+b; $b=$a; sleep 1.01 }'
Use of uninitialized value $b in subtraction (-) at -e line 1.
1579951233.92519 1579951233.92519
1579951234.92536 1.00017690658569
1579951235.92573 1.00036287307739
1579951236.92672 1.00098919868469
1579951237.93894 1.01222395896912
1579951238.95456 1.01561999320984
1579951239.97017 1.01561403274536
1579951240.98579 1.01561689376831
1579951242.00141 1.01561808586121 !!!!
1579951243.01703 1.01561903953552
$ perl -MTime::HiRes=time -le 'print $Time::HiRes::VERSION'
1.9741
$ perl --version
This is perl 5, version 26, subversion 3 (v5.26.3) built for x86_64-cy
+gwin-threads-multi
(with 7 registered patches, see perl -V for more detail)
Copyright 1987-2018, Larry Wall
Perl may be copied only under the terms of either the Artistic License
+ or the
GNU General Public License, which may be found in the Perl 5 source ki
+t.
Complete documentation for Perl, including FAQ lists, should be found
+on
this system using "man perl" or "perldoc perl". If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.
Also including output of perl -V for interested parties:
$ perl -V
Summary of my perl5 (revision 5 version 26 subversion 3) configuration
+:
Platform:
osname=cygwin
osvers=3.0.7(0.33853)
archname=x86_64-cygwin-threads-multi
uname='cygwin_nt-10.0 cygwinpro 3.0.7(0.33853) 2019-04-30 18:08 x8
+6_64 cygwin '
config_args='-des -Dprefix=/usr -Dmksymlinks -Darchname=x86_64-cyg
+win-threads -Dlibperl=cygperl5_26.dll -Dcc=gcc -Dld=g++ -Accflags=-gg
+db -O2 -pipe -Wall -Werror=format-security -D_FORTIFY_SOURCE=2 -fstac
+k-protector-strong --param=ssp-buffer-size=4 -fdebug-prefix-map=/mnt/
+share/cygpkgs/perl/perl.x86_64/build=/usr/src/debug/perl-5.26.3-2 -fd
+ebug-prefix-map=/mnt/share/cygpkgs/perl/perl.x86_64/src/perl-5.26.3=/
+usr/src/debug/perl-5.26.3-2 -fwrapv'
hint=recommended
useposix=true
d_sigaction=define
useithreads=define
usemultiplicity=define
use64bitint=define
use64bitall=define
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler:
cc='gcc'
ccflags ='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__ -D_GNU_SOURCE -
+ggdb -O2 -pipe -Wall -Werror=format-security -D_FORTIFY_SOURCE=2 -fst
+ack-protector-strong --param=ssp-buffer-size=4 -fdebug-prefix-map=/mn
+t/share/cygpkgs/perl/perl.x86_64/build=/usr/src/debug/perl-5.26.3-2 -
+fdebug-prefix-map=/mnt/share/cygpkgs/perl/perl.x86_64/src/perl-5.26.3
+=/usr/src/debug/perl-5.26.3-2 -fwrapv -fno-strict-aliasing'
optimize='-O3'
cppflags='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__ -D_GNU_SOURCE -
+ggdb -O2 -pipe -Wall -Werror=format-security -D_FORTIFY_SOURCE=2 -fst
+ack-protector-strong --param=ssp-buffer-size=4 -fdebug-prefix-map=/mn
+t/share/cygpkgs/perl/perl.x86_64/build=/usr/src/debug/perl-5.26.3-2 -
+fdebug-prefix-map=/mnt/share/cygpkgs/perl/perl.x86_64/src/perl-5.26.3
+=/usr/src/debug/perl-5.26.3-2 -fwrapv -fno-strict-aliasing'
ccversion=''
gccversion='7.4.0'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=3
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='g++'
ldflags =' -Wl,--enable-auto-import -Wl,--export-all-symbols -Wl,-
+-enable-auto-image-base -fstack-protector-strong'
libpth=/usr/lib
libs=-lpthread -lnsl -lgdbm -ldb -ldl -lcrypt -lgdbm_compat
perllibs=-lpthread -lnsl -ldl -lcrypt
libc=/usr/lib/libcygwin.a
so=dll
useshrplib=true
libperl=cygperl5_26.dll
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs
dlext=dll
d_dlsymun=undef
ccdlflags=' '
cccdlflags=' '
lddlflags=' --shared -Wl,--enable-auto-import -Wl,--export-all-sy
+mbols -Wl,--enable-auto-image-base -fstack-protector-strong'
Characteristics of this binary (from libperl):
Compile-time options:
HAS_TIMES
MULTIPLICITY
PERLIO_LAYERS
PERL_COPY_ON_WRITE
PERL_DONT_CREATE_GVSV
PERL_IMPLICIT_CONTEXT
PERL_OP_PARENT
PERL_PRESERVE_IVUV
PERL_USE_SAFE_PUTENV
USE_64_BIT_ALL
USE_64_BIT_INT
USE_ITHREADS
USE_LARGE_FILES
USE_LOCALE
USE_LOCALE_COLLATE
USE_LOCALE_CTYPE
USE_LOCALE_NUMERIC
USE_LOCALE_TIME
USE_PERLIO
USE_PERL_ATOF
USE_REENTRANT_API
Locally applied patches:
Cygwin: README
Cygwin: use auto-image-base instead of fixed DLL base address
Cygwin: modify hints
Cygwin: Configure correct libsearch
Cygwin: Configure correct libpth
Cygwin: Win32 correct UTF8 handling
Perl: File-Path-2.14 (fixes CVE2017-6512)
Built under cygwin
Compiled at Aug 24 2019 12:22:19
%ENV:
PERL5LIB="/Work/Perl/LIB"
PERL5OPT="-Mstrict -Mwarnings"
@INC:
/Work/Perl/LIB
/usr/local/lib/perl5/site_perl/5.26/x86_64-cygwin-threads
/usr/local/share/perl5/site_perl/5.26
/usr/lib/perl5/vendor_perl/5.26/x86_64-cygwin-threads
/usr/share/perl5/vendor_perl/5.26
/usr/lib/perl5/5.26/x86_64-cygwin-threads
/usr/share/perl5/5.26
...roboticus
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