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Description
Description
If youshmread into a tied buffer, perl calls not justSTORE to store the result (as expected), but alsoFETCH. This makes no sense becauseshmread is conceptually an assignment to the buffer variable: it overwrites the contents and does not care about the previous value.
Steps to Reproduce
use warnings;use strict;use IPC::SysVqw(IPC_PRIVATE IPC_RMID S_IRUSR S_IWUSR); {packageWronly;subTIESCALAR {bless {},$_[0] }subSTORE {printqq("storing"$_[1]\n); }subFETCH {die"FETCH not supported"; }}my$key =shmget(IPC_PRIVATE, 123, S_IRUSR | S_IWUSR) //die"shmget():$!";END {shmctl($key, IPC_RMID, 0) //warn"shmctl($key, IPC_RMID, 0):$!"ifdefined$key;}my$msg ="Hello!";shmwrite($key,$msg, 0,length$msg)ordie"shmwrite():$!";tiemy$fake_buf,'Wronly';shmread($key,$fake_buf, 0,length$msg)ordie"shmread():$!";
Output:
FETCH not supported at try.pl line 10.Expected behavior
"storing" Hello!Perl configuration
Summary of my perl5 (revision 5 version 40 subversion 0) configuration: Platform: osname=linux osvers=6.5.0-10040-tuxedo archname=x86_64-linux-thread-multi-ld uname='linux luum 6.5.0-10040-tuxedo #44 smp preempt_dynamic wed may 8 17:36:39 utc 2024 x86_64 x86_64 x86_64 gnulinux ' config_args='-de -Dprefix=/home/mauke/perl5/perlbrew/perls/perl-5.40.0 -Dcc=cgcc -Dman1dir=none -Dman3dir=none -Dusethreads -Duselongdouble -Aoptimize=-flto -Aeval:scriptdir=/home/mauke/perl5/perlbrew/perls/perl-5.40.0/bin' hint=recommended useposix=true d_sigaction=define useithreads=define usemultiplicity=define use64bitint=define use64bitall=define uselongdouble=define usemymalloc=n default_inc_excludes_dot=define Compiler: cc='cgcc' ccflags ='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64' optimize='-O2 -flto' cppflags='-D_REENTRANT -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include' ccversion='' gccversion='11.4.0' 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='long double' nvsize=16 Off_t='off_t' lseeksize=8 alignbytes=16 prototype=define Linker and Libraries: ld='cgcc' ldflags =' -fstack-protector-strong -L/usr/local/lib' libpth=/usr/local/lib /usr/lib/x86_64-linux-gnu /usr/lib /usr/lib64 libs=-lpthread -ldb -ldl -lm -lcrypt -lutil -lc perllibs=-lpthread -ldl -lm -lcrypt -lutil -lc libc=/lib/x86_64-linux-gnu/libc.so.6 so=so useshrplib=false libperl=libperl.a gnulibc_version='2.35' Dynamic Linking: dlsrc=dl_dlopen.xs dlext=so d_dlsymun=undef ccdlflags='-Wl,-E' cccdlflags='-fPIC' lddlflags='-shared -O2 -flto -L/usr/local/lib -fstack-protector-strong'Characteristics of this binary (from libperl): Compile-time options: HAS_LONG_DOUBLE HAS_STRTOLD HAS_TIMES MULTIPLICITY PERLIO_LAYERS PERL_COPY_ON_WRITE PERL_DONT_CREATE_GVSV PERL_HASH_FUNC_SIPHASH13 PERL_HASH_USE_SBOX32 PERL_MALLOC_WRAP 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_LONG_DOUBLE USE_PERLIO USE_PERL_ATOF USE_REENTRANT_API USE_THREAD_SAFE_LOCALE Built under linux Compiled at Jun 9 2024 23:04:17 %ENV: PERLBREW_BASHRC_VERSION="0.74" PERLBREW_HOME="/home/mauke/.perlbrew" PERLBREW_MANPATH="/home/mauke/perl5/perlbrew/perls/perl-5.40.0/man" PERLBREW_PATH="/home/mauke/perl5/perlbrew/bin:/home/mauke/perl5/perlbrew/perls/perl-5.40.0/bin" PERLBREW_PERL="perl-5.40.0" PERLBREW_ROOT="/home/mauke/perl5/perlbrew" PERLBREW_VERSION="0.98" PERLDOC="-oman" @INC: /home/mauke/perl5/perlbrew/perls/perl-5.40.0/lib/site_perl/5.40.0/x86_64-linux-thread-multi-ld /home/mauke/perl5/perlbrew/perls/perl-5.40.0/lib/site_perl/5.40.0 /home/mauke/perl5/perlbrew/perls/perl-5.40.0/lib/5.40.0/x86_64-linux-thread-multi-ld /home/mauke/perl5/perlbrew/perls/perl-5.40.0/lib/5.40.0