Security Advisories (19)
Perl for Windows relies on the system path environment variable to find the shell (cmd.exe). When running an executable which uses Windows Perl interpreter, Perl attempts to find and execute cmd.exe within the operating system. However, due to path search order issues, Perl initially looks for cmd.exe in the current working directory. An attacker with limited privileges can exploit this behavior by placing cmd.exe in locations with weak permissions, such as C:\ProgramData. By doing so, when an administrator attempts to use this executable from these compromised locations, arbitrary code can be executed.
Perl threads have a working directory race condition where file operations may target unintended paths. If a directory handle is open at thread creation, the process-wide current working directory is temporarily changed in order to clone that handle for the new thread, which is visible from any third (or more) thread already running. This may lead to unintended operations such as loading code or accessing files from unexpected locations, which a local attacker may be able to exploit. The bug was introduced in commit 11a11ecf4bea72b17d250cfb43c897be1341861e and released in Perl version 5.13.6
- https://github.com/Perl/perl5/commit/918bfff86ca8d6d4e4ec5b30994451e0bd74aba9.patch
- https://www.openwall.com/lists/oss-security/2025/05/22/2
- https://github.com/Perl/perl5/issues/23010
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1098226
- https://github.com/Perl/perl5/issues/10387
- https://perldoc.perl.org/5.14.0/perl5136delta#Directory-handles-not-copied-to-threads
- https://github.com/Perl/perl5/commit/11a11ecf4bea72b17d250cfb43c897be1341861e
Heap-based buffer overflow in the Perl_repeatcpy function in util.c in Perl 5.12.x before 5.12.5, 5.14.x before 5.14.3, and 5.15.x before 15.15.5 allows context-dependent attackers to cause a denial of service (memory consumption and crash) or possibly execute arbitrary code via the 'x' string repeat operator.
- http://perl5.git.perl.org/perl.git/commit/2709980d5a193ce6f3a16f0d19879a6560dcde44
- http://www.nntp.perl.org/group/perl.perl5.porters/2012/10/msg193886.html
- http://www.securityfocus.com/bid/56287
- http://www.openwall.com/lists/oss-security/2012/10/27/1
- http://secunia.com/advisories/51457
- http://www.openwall.com/lists/oss-security/2012/10/26/2
- http://www.ubuntu.com/usn/USN-1643-1
- http://www.debian.org/security/2012/dsa-2586
- http://rhn.redhat.com/errata/RHSA-2013-0685.html
- http://secunia.com/advisories/55314
- http://www.mandriva.com/security/advisories?name=MDVSA-2013:113
- https://wiki.mageia.org/en/Support/Advisories/MGASA-2012-0352
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10735
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10673
Integer underflow in regcomp.c in Perl before 5.20, as used in Apple OS X before 10.10.5 and other products, allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via a long digit string associated with an invalid backreference within a regular expression.
- http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
- https://support.apple.com/kb/HT205031
- http://perl5.git.perl.org/perl.git/commit/0c2990d652e985784f095bba4bc356481a66aa06
- http://www.securityfocus.com/bid/75704
- http://www.ubuntu.com/usn/USN-2916-1
- https://security.gentoo.org/glsa/201507-11
Perl before 5.26.3 has a buffer overflow via a crafted regular expression that triggers invalid write operations.
- https://www.debian.org/security/2018/dsa-4347
- https://rt.perl.org/Ticket/Display.html?id=131649
- https://metacpan.org/changes/release/SHAY/perl-5.26.3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RWQGEB543QN7SSBRKYJM6PSOC3RLYGSM/
- https://github.com/Perl/perl5/commit/19a498a461d7c81ae3507c450953d1148efecf4f
- https://bugzilla.redhat.com/show_bug.cgi?id=1646751
- http://www.securitytracker.com/id/1042181
- https://usn.ubuntu.com/3834-1/
- http://www.securityfocus.com/bid/106145
- https://access.redhat.com/errata/RHSA-2019:0010
- https://access.redhat.com/errata/RHSA-2019:0001
- https://security.netapp.com/advisory/ntap-20190221-0003/
- https://security.gentoo.org/glsa/201909-01
- https://www.oracle.com/security-alerts/cpujul2020.html
Perl before 5.26.3 has a buffer over-read via a crafted regular expression that triggers disclosure of sensitive information from process memory.
- https://www.debian.org/security/2018/dsa-4347
- https://usn.ubuntu.com/3834-2/
- https://rt.perl.org/Ticket/Display.html?id=133192
- https://metacpan.org/changes/release/SHAY/perl-5.26.3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RWQGEB543QN7SSBRKYJM6PSOC3RLYGSM/
- https://github.com/Perl/perl5/commit/43b2f4ef399e2fd7240b4eeb0658686ad95f8e62
- https://bugzilla.redhat.com/show_bug.cgi?id=1646738
- http://www.securitytracker.com/id/1042181
- https://usn.ubuntu.com/3834-1/
- https://access.redhat.com/errata/RHSA-2019:0010
- https://access.redhat.com/errata/RHSA-2019:0001
- https://security.netapp.com/advisory/ntap-20190221-0003/
- https://support.apple.com/kb/HT209600
- https://seclists.org/bugtraq/2019/Mar/42
- http://seclists.org/fulldisclosure/2019/Mar/49
- https://security.gentoo.org/glsa/201909-01
- https://www.oracle.com/security-alerts/cpujul2020.html
Perl before 5.26.3 and 5.28.0 before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.
- https://www.debian.org/security/2018/dsa-4347
- https://rt.perl.org/Public/Bug/Display.html?id=133423
- https://metacpan.org/changes/release/SHAY/perl-5.28.1
- https://metacpan.org/changes/release/SHAY/perl-5.26.3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RWQGEB543QN7SSBRKYJM6PSOC3RLYGSM/
- https://bugzilla.redhat.com/show_bug.cgi?id=1646734
- http://www.securitytracker.com/id/1042181
- https://usn.ubuntu.com/3834-1/
- http://www.securityfocus.com/bid/106179
- https://access.redhat.com/errata/RHSA-2019:0010
- https://access.redhat.com/errata/RHSA-2019:0001
- https://security.netapp.com/advisory/ntap-20190221-0003/
- https://security.gentoo.org/glsa/201909-01
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://perldoc.perl.org/perl5281delta
- https://perldoc.perl.org/perl5263delta
Perl might allow context-dependent attackers to bypass the taint protection mechanism in a child process via duplicate environment variables in envp.
- http://www.gossamer-threads.com/lists/perl/porters/326387
- http://www.debian.org/security/2016/dsa-3501
- http://perl5.git.perl.org/perl.git/commitdiff/ae37b791a73a9e78dedb89fb2429d2628cf58076
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- http://www.securityfocus.com/bid/83802
- http://www.ubuntu.com/usn/USN-2916-1
- http://lists.opensuse.org/opensuse-updates/2016-03/msg00112.html
- https://security.gentoo.org/glsa/201701-75
- http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
In Perl before 5.38.2, S_parse_uniprop_string in regcomp.c can write to unallocated space because a property name associated with a \p{...} regular expression construct is mishandled. The earliest affected version is 5.30.0.
(1) cpan/Archive-Tar/bin/ptar, (2) cpan/Archive-Tar/bin/ptardiff, (3) cpan/Archive-Tar/bin/ptargrep, (4) cpan/CPAN/scripts/cpan, (5) cpan/Digest-SHA/shasum, (6) cpan/Encode/bin/enc2xs, (7) cpan/Encode/bin/encguess, (8) cpan/Encode/bin/piconv, (9) cpan/Encode/bin/ucmlint, (10) cpan/Encode/bin/unidump, (11) cpan/ExtUtils-MakeMaker/bin/instmodsh, (12) cpan/IO-Compress/bin/zipdetails, (13) cpan/JSON-PP/bin/json_pp, (14) cpan/Test-Harness/bin/prove, (15) dist/ExtUtils-ParseXS/lib/ExtUtils/xsubpp, (16) dist/Module-CoreList/corelist, (17) ext/Pod-Html/bin/pod2html, (18) utils/c2ph.PL, (19) utils/h2ph.PL, (20) utils/h2xs.PL, (21) utils/libnetcfg.PL, (22) utils/perlbug.PL, (23) utils/perldoc.PL, (24) utils/perlivp.PL, and (25) utils/splain.PL in Perl 5.x before 5.22.3-RC2 and 5.24 before 5.24.1-RC2 do not properly remove . (period) characters from the end of the includes directory array, which might allow local users to gain privileges via a Trojan horse module under the current working directory.
- https://perldoc.perl.org/5.24.1/perldelta
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00002.html
- http://perl5.git.perl.org/perl.git/commit/cee96d52c39b1e7b36e1c62d38bcd8d86e9a41ab
- http://www.debian.org/security/2016/dsa-3628
- http://www.nntp.perl.org/group/perl.perl5.porters/2016/07/msg238271.html
- http://www.securityfocus.com/bid/92136
- http://www.securitytracker.com/id/1036440
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
- https://lists.apache.org/thread.html/7f6a16bc0fd0fd5e67c7fd95bd655069a2ac7d1f88e42d3c853e601c%40%3Cannounce.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2018/11/msg00016.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2FBQOCV3GBAN2EYZUM3CFDJ4ECA3GZOK/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DOFRQWJRP2NQJEYEWOMECVW3HAMD5SYN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TZBNQH3DMI7HDELJAZ4TFJJANHXOEDWH/
- https://rt.perl.org/Public/Bug/Display.html?id=127834
- https://security.gentoo.org/glsa/201701-75
- https://security.gentoo.org/glsa/201812-07
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00002.html
- http://perl5.git.perl.org/perl.git/commit/cee96d52c39b1e7b36e1c62d38bcd8d86e9a41ab
- http://www.debian.org/security/2016/dsa-3628
- http://www.nntp.perl.org/group/perl.perl5.porters/2016/07/msg238271.html
- http://www.securityfocus.com/bid/92136
- http://www.securitytracker.com/id/1036440
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
- https://lists.apache.org/thread.html/7f6a16bc0fd0fd5e67c7fd95bd655069a2ac7d1f88e42d3c853e601c%40%3Cannounce.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2018/11/msg00016.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2FBQOCV3GBAN2EYZUM3CFDJ4ECA3GZOK/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DOFRQWJRP2NQJEYEWOMECVW3HAMD5SYN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TZBNQH3DMI7HDELJAZ4TFJJANHXOEDWH/
- https://rt.perl.org/Public/Bug/Display.html?id=127834
- https://security.gentoo.org/glsa/201701-75
- https://security.gentoo.org/glsa/201812-07
The VDir::MapPathA and VDir::MapPathW functions in Perl 5.22 allow remote attackers to cause a denial of service (out-of-bounds read) and possibly execute arbitrary code via a crafted (1) drive letter or (2) pInName argument.
- https://rt.perl.org/Public/Bug/Display.html?id=126755
- https://github.com/Perl/perl5/issues/15067
- https://packetstormsecurity.com/files/136649/Perl-5.22-VDir-MapPathA-W-Out-Of-Bounds-Reads-Buffer-Over-Reads.html
- http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html
- https://www.oracle.com/security-alerts/cpujul2020.html
The bsd_glob function in the File::Glob module for Perl before 5.14.2 allows context-dependent attackers to cause a denial of service (crash) via a glob expression with the GLOB_ALTDIRFUNC flag, which triggers an uninitialized pointer dereference.
- http://lists.fedoraproject.org/pipermail/package-announce/2011-November/069752.html
- http://www.securityfocus.com/bid/49858
- http://cpansearch.perl.org/src/FLORA/perl-5.14.2/pod/perldelta.pod
- http://perl5.git.perl.org/perl.git/commit/1af4051e077438976a4c12a0622feaf6715bec77
- http://secunia.com/advisories/46172
- https://blogs.oracle.com/sunsecurity/entry/cve_2011_2728_denial_of1
- https://bugzilla.redhat.com/show_bug.cgi?id=742987
regcomp.c in Perl before 5.30.3 allows a buffer overflow via a crafted regular expression because of recursive S_study_chunk calls.
- https://github.com/Perl/perl5/compare/v5.30.2...v5.30.3
- https://github.com/Perl/perl5/blob/blead/pod/perl5303delta.pod
- https://github.com/Perl/perl5/issues/16947
- https://github.com/perl/perl5/commit/66bbb51b93253a3f87d11c2695cfb7bdb782184a
- https://github.com/Perl/perl5/issues/17743
- https://security.netapp.com/advisory/ntap-20200611-0001/
- https://security.gentoo.org/glsa/202006-03
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IN3TTBO5KSGWE5IRIKDJ5JSQRH7ANNXE/
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00044.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://perldoc.perl.org/perl5283delta
- https://perldoc.perl.org/perl5303delta
- https://perldoc.perl.org/perl5320delta
Perl before 5.30.3 has an integer overflow related to mishandling of a "PL_regkind[OP(n)] == NOTHING" situation. A crafted regular expression could lead to malformed bytecode with a possibility of instruction injection.
- https://github.com/Perl/perl5/compare/v5.30.2...v5.30.3
- https://github.com/perl/perl5/commit/3295b48defa0f8570114877b063fe546dd348b3c
- https://github.com/perl/perl5/commit/0a320d753fe7fca03df259a4dfd8e641e51edaa8
- https://github.com/Perl/perl5/blob/blead/pod/perl5303delta.pod
- https://security.netapp.com/advisory/ntap-20200611-0001/
- https://security.gentoo.org/glsa/202006-03
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IN3TTBO5KSGWE5IRIKDJ5JSQRH7ANNXE/
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00044.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://perldoc.perl.org/perl5283delta
- https://perldoc.perl.org/perl5303delta
- https://perldoc.perl.org/perl5320delta
Perl before 5.30.3 on 32-bit platforms allows a heap-based buffer overflow because nested regular expression quantifiers have an integer overflow.
- https://github.com/Perl/perl5/compare/v5.30.2...v5.30.3
- https://github.com/perl/perl5/commit/897d1f7fd515b828e4b198d8b8bef76c6faf03ed
- https://github.com/Perl/perl5/blob/blead/pod/perl5303delta.pod
- https://security.netapp.com/advisory/ntap-20200611-0001/
- https://security.gentoo.org/glsa/202006-03
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IN3TTBO5KSGWE5IRIKDJ5JSQRH7ANNXE/
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00044.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://perldoc.perl.org/perl5283delta
- https://perldoc.perl.org/perl5303delta
- https://perldoc.perl.org/perl5320delta
Heap-based buffer overflow in the pack function in Perl before 5.26.2 allows context-dependent attackers to execute arbitrary code via a large item count.
- https://www.debian.org/security/2018/dsa-4172
- https://rt.perl.org/Public/Bug/Display.html?id=131844
- https://lists.debian.org/debian-lts-announce/2018/04/msg00009.html
- http://www.securitytracker.com/id/1040681
- https://usn.ubuntu.com/3625-2/
- https://usn.ubuntu.com/3625-1/
- http://www.securityfocus.com/bid/103953
- https://security.gentoo.org/glsa/201909-01
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://perldoc.perl.org/perl5244delta
- https://perldoc.perl.org/perl5262delta
- https://github.com/Perl/perl5/issues/16098
Perl before 5.26.3 and 5.28.x before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.
- https://www.debian.org/security/2018/dsa-4347
- https://usn.ubuntu.com/3834-2/
- https://rt.perl.org/Ticket/Display.html?id=133204
- https://metacpan.org/changes/release/SHAY/perl-5.28.1
- https://metacpan.org/changes/release/SHAY/perl-5.26.3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RWQGEB543QN7SSBRKYJM6PSOC3RLYGSM/
- https://lists.debian.org/debian-lts-announce/2018/11/msg00039.html
- https://github.com/Perl/perl5/commit/34716e2a6ee2af96078d62b065b7785c001194be
- https://bugzilla.redhat.com/show_bug.cgi?id=1646730
- http://www.securitytracker.com/id/1042181
- https://usn.ubuntu.com/3834-1/
- http://www.securityfocus.com/bid/106145
- https://access.redhat.com/errata/RHSA-2019:0010
- https://access.redhat.com/errata/RHSA-2019:0001
- https://access.redhat.com/errata/RHSA-2019:0109
- https://security.netapp.com/advisory/ntap-20190221-0003/
- https://support.apple.com/kb/HT209600
- https://seclists.org/bugtraq/2019/Mar/42
- http://seclists.org/fulldisclosure/2019/Mar/49
- https://kc.mcafee.com/corporate/index?page=content&id=SB10278
- https://access.redhat.com/errata/RHBA-2019:0327
- https://access.redhat.com/errata/RHSA-2019:1790
- https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html
- https://access.redhat.com/errata/RHSA-2019:1942
- https://access.redhat.com/errata/RHSA-2019:2400
- https://security.gentoo.org/glsa/201909-01
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://perldoc.perl.org/perl5281delta
- https://perldoc.perl.org/perl5263delta
The (1) S_reghop3, (2) S_reghop4, and (3) S_reghopmaybe3 functions in regexec.c in Perl before 5.24.0 allow context-dependent attackers to cause a denial of service (infinite loop) via crafted utf-8 data, as demonstrated by "a\x80."
- http://lists.fedoraproject.org/pipermail/package-announce/2016-May/183592.html
- http://www.openwall.com/lists/oss-security/2016/04/20/7
- https://bugzilla.redhat.com/show_bug.cgi?id=1329106
- https://rt.perl.org/Public/Bug/Display.html?id=123562
- http://www.openwall.com/lists/oss-security/2016/04/20/5
- http://perl5.git.perl.org/perl.git/commitdiff/22b433eff9a1ffa2454e18405a56650f07b385b5
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05240731
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- http://www.securityfocus.com/bid/86707
- https://security.gentoo.org/glsa/201701-75
- https://usn.ubuntu.com/3625-2/
- https://usn.ubuntu.com/3625-1/
The rehash mechanism in Perl 5.8.2 through 5.16.x allows context-dependent attackers to cause a denial of service (memory consumption and crash) via a crafted hash key.
- http://www.securityfocus.com/bid/58311
- http://perl5.git.perl.org/perl.git/commitdiff/d59e31f
- http://perl5.git.perl.org/perl.git/commitdiff/9d83adc
- http://www.nntp.perl.org/group/perl.perl5.porters/2013/03/msg199755.html
- http://www.debian.org/security/2013/dsa-2641
- http://secunia.com/advisories/52499
- http://secunia.com/advisories/52472
- https://bugzilla.redhat.com/show_bug.cgi?id=912276
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702296
- http://perl5.git.perl.org/perl.git/commitdiff/6e79fe5
- http://osvdb.org/90892
- http://www.ubuntu.com/usn/USN-1770-1
- http://rhn.redhat.com/errata/RHSA-2013-0685.html
- http://lists.apple.com/archives/security-announce/2013/Oct/msg00004.html
- http://marc.info/?l=bugtraq&m=137891988921058&w=2
- http://www.mandriva.com/security/advisories?name=MDVSA-2013:113
- https://wiki.mageia.org/en/Support/Advisories/MGASA-2013-0094
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10735
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705
- https://exchange.xforce.ibmcloud.com/vulnerabilities/82598
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18771
NAME
Tie::Scalar, Tie::StdScalar - base class definitions for tied scalars
SYNOPSIS
package NewScalar;
require Tie::Scalar;
@ISA = qw(Tie::Scalar);
sub FETCH { ... } # Provide a needed method
sub TIESCALAR { ... } # Overrides inherited method
package NewStdScalar;
require Tie::Scalar;
@ISA = qw(Tie::StdScalar);
# All methods provided by default, so define only what needs be overridden
sub FETCH { ... }
package main;
tie $new_scalar, 'NewScalar';
tie $new_std_scalar, 'NewStdScalar';
DESCRIPTION
This module provides some skeletal methods for scalar-tying classes. See perltie for a list of the functions required in tying a scalar to a package. The basic Tie::Scalar package provides a new method, as well as methods TIESCALAR, FETCH and STORE. The Tie::StdScalar package provides all the methods specified in perltie. It inherits from Tie::Scalar and causes scalars tied to it to behave exactly like the built-in scalars, allowing for selective overloading of methods. The new method is provided as a means of grandfathering, for classes that forget to provide their own TIESCALAR method.
For developers wishing to write their own tied-scalar classes, the methods are summarized below. The perltie section not only documents these, but has sample code as well:
- TIESCALAR classname, LIST
-
The method invoked by the command
tie $scalar, classname. Associates a new scalar instance with the specified class.LISTwould represent additional arguments (along the lines of AnyDBM_File and compatriots) needed to complete the association. - FETCH this
-
Retrieve the value of the tied scalar referenced by this.
- STORE this, value
-
Store data value in the tied scalar referenced by this.
- DESTROY this
-
Free the storage associated with the tied scalar referenced by this. This is rarely needed, as Perl manages its memory quite well. But the option exists, should a class wish to perform specific actions upon the destruction of an instance.
Tie::Scalar vs Tie::StdScalar
Tie::Scalar provides all the necessary methods, but one should realize they do not do anything useful. Calling Tie::Scalar::FETCH or Tie::Scalar::STORE results in a (trappable) croak. And if you inherit from Tie::Scalar, you must provide either a new or a TIESCALAR method.
If you are looking for a class that does everything for you you don't define yourself, use the Tie::StdScalar class, not the Tie::Scalar one.
MORE INFORMATION
The perltie section uses a good example of tying scalars by associating process IDs with priority.
Module Install Instructions
To install P5re, copy and paste the appropriate command in to your terminal.
cpanm P5re
perl -MCPAN -e shell
install P5re
For more information on module installation, please visit the detailed CPAN module installation guide.