p5pRT
commented
23 years ago From sburke@spinn.net
The bug seems unaffected by the presence or absensce of "use utf8".
I've observed this bug under 5.6.0 under MSWin (ME and 98) /and/ Linux (three different machines incidentally)\, and under 5.00305 under AIX; those are all the systems I've tested this under.
Below are perl -V outputs on the three platforms\, and then a program reproducing the bug in many iterations.
I note that the bug seems to appear /only/ when there is an OS locale active /and/ use locale is on /and/ we try to evaluate substr(...) cmp substr(...) in scope of the "use locale". Very odd indeed! Good luck finding a fix for this.
Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration: Platform: osname=aix\, osvers=4.3.1.0\, archname=aix uname='aix pegasus 3 4 000165185700 ' hint=recommended\, useposix=true\, d_sigaction=define usethreads=undef useperlio=undef d_sfio=undef Compiler: cc='cc'\, optimize='-O'\, gccversion= cppflags='-D_ALL_SOURCE -D_ANSI_C_SOURCE -D_POSIX_SOURCE -qmaxmem=8192 -I/usr/local/include -I/usr/local/gnu/include' ccflags ='-D_ALL_SOURCE -D_ANSI_C_SOURCE -D_POSIX_SOURCE -qmaxmem=8192 -I/usr/local/include -I/usr/local/gnu/include' stdchar='unsigned char'\, d_stdstdio=define\, usevfork=false intsize=4\, longsize=4\, ptrsize=4\, doublesize=8 d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=8 alignbytes=8\, usemymalloc=n\, prototype=define Linker and Libraries: ld='ld'\, ldflags ='-L/usr/local/lib -L/usr/local/gnu/lib -L/usr/ccs/lib -L/lib' libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib /usr/local/gnu/lib libs=-lnsl -lgdbm -ldbm -ldl -lld -lm -lc -lcrypt -lbsd -lPW libc=\, so=a\, useshrplib=false\, libperl=libperl.a Dynamic Linking: dlsrc=dl_aix.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags='-bE:perl.exp' cccdlflags=' '\, lddlflags='-bhalt:4 -bM:SRE -bI:$(PERL_INC)/perl.exp -bE:$(BASEEXT).exp -b noentry -lc -L/usr/local/lib -L/usr/local/gnu/lib -L/usr/ccs/lib -L/lib'
Characteristics of this binary (from libperl): Built under aix Compiled at Aug 12 1999 09:10:29 %ENV: PERLLIB="/nfs/user/l/lachler/.bin/perl/aix:/nfs/user/l/lachler/.bin/perl" [and\, not shown\, LANG="en_US"]
@INC: /nfs/user/l/lachler/.bin/perl/aix /nfs/user/l/lachler/.bin/perl /usr/local/gnu/lib/perl5/5.00503/aix /usr/local/gnu/lib/perl5/5.00503 /usr/local/gnu/lib/perl5/site_perl/5.005/aix /usr/local/gnu/lib/perl5/site_perl/5.005 .
Summary of my perl5 (revision 5.0 version 6 subversion 0) configuration: Platform: osname=linux\, osvers=2.2.16-21\, archname=i686-linux uname='linux spinntwo 2.2.16-21 #1 wed aug 9 10:38:45 edt 2000 i686 unknown ' config_args='' hint=recommended\, useposix=true\, d_sigaction=define usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef useperlio=undef d_sfio=undef uselargefiles=define use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef Compiler: cc='cc'\, optimize='-O2'\, gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release) cppflags='-fno-strict-aliasing -I/usr/local/include' ccflags ='-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64' stdchar='char'\, d_stdstdio=define\, usevfork=false intsize=4\, longsize=4\, ptrsize=4\, doublesize=8 d_longlong=define\, longlongsize=8\, d_longdbl=define\, longdblsize=12 ivtype='long'\, ivsize=4\, nvtype='double'\, nvsize=8\, Off_t='off_t'\, lseeksize=8 alignbytes=4\, usemymalloc=n\, prototype=define Linker and Libraries: ld='cc'\, ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lnsl -lndbm -ldb -ldl -lm -lc -lposix -lcrypt libc=/lib/libc-2.1.3.so\, so=so\, useshrplib=false\, libperl=libperl.a Dynamic Linking: dlsrc=dl_dlopen.xs\, dlext=so\, d_dlsymun=undef\, ccdlflags='-rdynamic' cccdlflags='-fpic'\, lddlflags='-shared -L/usr/local/lib'
Characteristics of this binary (from libperl): Compile-time options: USE_LARGE_FILES Built under linux Compiled at Oct 27 2000 18:12:05 %ENV: PERLLIB="/home/users/s/sburke/.bin/perl/" [and\, not shown\, LANG="en_US"]
@INC: /home/users/s/sburke/.bin/perl/ /usr/lib/perl5/5.6.0/i686-linux /usr/lib/perl5/5.6.0 /usr/lib/perl5/site_perl/5.6.0/i686-linux /usr/lib/perl5/site_perl/5.6.0 /usr/lib/perl5/site_perl/5.005 /usr/lib/perl5/site_perl .
Summary of my perl5 (revision 5 version 6 subversion 0) configuration: Platform: osname=MSWin32\, osvers=4.0\, archname=MSWin32-x86-multi-thread uname='' config_args='undef' hint=recommended\, useposix=true\, d_sigaction=undef usethreads=undef use5005threads=undef useithreads=define usemultiplicity=define useperlio=undef d_sfio=undef uselargefiles=undef use64bitint=undef use64bitall=undef uselongdouble=undef usesocks=undef Compiler: cc='cl'\, optimize='-O1 -MD -DNDEBUG'\, gccversion= cppflags='-DWIN32' ccflags ='-O1 -MD -DNDEBUG -DWIN32 -D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DPERL_MSVCRT_READFIX' stdchar='char'\, d_stdstdio=define\, usevfork=false intsize=4\, longsize=4\, ptrsize=4\, doublesize=8 d_longlong=undef\, longlongsize=8\, d_longdbl=define\, longdblsize=10 ivtype='long'\, ivsize=4\, nvtype='double'\, nvsize=8\, Off_t='off_t'\, lseeksize=4 alignbytes=8\, usemymalloc=n\, prototype=define Linker and Libraries: ld='link'\, ldflags ='-nologo -nodefaultlib -release -libpath:"C:\Perl\lib\CORE" -machine:x86' libpth="C:\Perl\lib\CORE" libs= oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib uuid.lib wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib libc=msvcrt.lib\, so=dll\, useshrplib=yes\, libperl=perl56.lib Dynamic Linking: dlsrc=dl_win32.xs\, dlext=dll\, d_dlsymun=undef\, ccdlflags=' ' cccdlflags=' '\, lddlflags='-dll -nologo -nodefaultlib -release -libpath:"C:\Perl\lib\CORE" -machine:x86'
Characteristics of this binary (from libperl): Compile-time options: MULTIPLICITY USE_ITHREADS PERL_IMPLICIT_CONTEXT PERL_IMPLICIT_SYS Locally applied patches: ActivePerl Build 623 Built under MSWin32 Compiled at Dec 15 2000 16:27:07 %ENV: PERLDOC_PAGER="towrite" @INC: C:/Perl/lib C:/Perl/site/lib . [and a Control Panel "Regional Settings" value of "English (United States)" -- altho changing to different locales (Russian\, French\, Italian...) doesn't seem to make the bug go away.]
And now the program exhibiting the bug:
# Under 5.6.0 and 5.00503\, this screams like a baby under LANG=en_US\, # /or/ under MSWin! # Commenting out 'use locale' makes the bug go away\, as does (under # UNIX) unsetenv LANG. # Time-stamp: "2001-05-10 01:40:16 MDT"
print "Perl version $]\n"; use strict; use locale; my $r = .75; my $bad = 0; my $all = 0; print "R: $r\n"; for(1 .. 1000) { my $x = "foobar"; my $y = "fooa"; ($x\,$y) = ($y\,$x) if rand > $r;
my $cmp1 = substr($x\,0\,4) cmp substr($y\,0\,4); my $i = substr($x\,0\,4); my $j = substr($y\,0\,4); my $cmp2 = $i cmp $j;
# The following two lines are never run:
print "****SCREAM1\n" unless $i eq substr($x\,0\,4);
print "****SCREAM2\n" unless $j eq substr($y\,0\,4);
if($cmp1 != $cmp2) {
++$bad;
print "SCREAM! ";
} else {
print "okay ";
}
++$all;
printf "%2s : %2s \<%s>\<%s> from \<%s> \<%s>\n"\,
$cmp1\,$cmp2\, $i\,$j\, $x\,$y;
}
printf "\n\nPct bad: %g%% (%g of %g); Cf. r=%g\n"\,
100 * $bad / $all\, $bad\, $all\, $r;
__END__
Output:
Perl version 5.006
R: 0.75
okay -1 : -1 \
Pct bad: 72.4% (724 of 1000); Cf. r=0.75
You'll note that in the dump above\, you get a scream IFF "foob" is first. Usually when I run the exact same program\, however\, I get a scream IFF "foob" ISN'T first.
As I run this more\, it seems to be the case that the pct-bad seems to vary directly with R /or/ 1-R. With an R of .75\, 75% of the time\, pct-bad is 25%\, and 25% of the time\, it's 75%. This relationship (N% of runs report percent-bads of approx 100-N%\, and vice versa) seems to hold between .5 and 1\, but seems to flip below .5 (i.e.\, N% of runs report percent-bads of approx N%\, and 100-N% of instances have 100-N% percent-bads.)
Migrated from rt.perl.org#6985 (status was 'resolved')
Searchable as RT6985$