$0 may be edited to longer lengths (at least under OS/2).
OS2::REXX->loads looks in the OS/2-ish fashion too.
+after 5.004_04:
+ Default perl.exe was built with a shorter stack than expected.
+ Strip extensions DLLs too (unless debugging build).
+ ./os2.c being RO could stop cp.
+ When starting scripts, Perl will find them on path (using the same
+ extensions as for -S command-line switch). If it finds magic
+ `extproc ' or `#!' cookies, it will start the scripts directly.
+ May use `cmd /c more <' as a pager.
+ If a program could not be started, this might have been hidden.
+ End of pipe was closed twice when `open'ing a pipeline.
+
after 5.004_53:
Minimal thread support added. One needs to manually move pthread.h
+
+after 5.004_64:
+ Make DLL names different if thread-enabled.
+ Emit more informative internal DLL descriptions.
+
+5.004_72:
+ Updated OS2::Process (v0.2) included.
+
+after 5.004_73:
+ Fixed a bug with argv not NULL-terminated when starting scripts.
+ Support all the forms of starting scripts.
+ Support killing a child when receiving a signal during system()
+ (in two stage, on first send the same signal, on the next
+ send SIGKILL).
+ Add the same logic for scripts as in pdksh, including
+ stripping the path from #! line if needed,
+ calling EXECSHELL or COMSPEC for magic-less scripts;
+ Now pdksh is called only if one-arg system()/friends contains
+ metachars, or if magic-line asks for sh, or there is no magic
+ line and EXECSHELL is set to sh.
+ Shell is supplied the original command line if possible.
+
+after 5.005_02:
+ Can start PM programs from non-PM sessions by plain system()
+ and friends. Can start DOS/Win programs. Can start
+ fullscreen programs from non-fullscreen sessions too.
+ In fact system(P_PM,...) was broken.
+ We mangle the name of perl*.DLL, to allow coexistence of different
+ versions of Perl executables on the system. Mangling of
+ names of extension DLL is also changed, thus running two
+ different versions of the executable with loaded
+ extensions should not lead to conflicts (since
+ extension-full-name and Perl-version mangling work in the
+ same set ot 576 possible keys, this may lead to clashes).
+ $^E was reset on the second read, and contained ".\r\n" at the end.
+
+after 5.005_53:
+ Would segfault system()ing non-existing program;
+ AOUT build was hosed;
+ warning-test for getpriority() might lock the system hard on
+ pre-fixpak22 configuration (calling getpriority() on
+ non-existing process triggers a system-wide bug).
+
+ Variable $OS2::emx_rev implemented (string and numberic values
+ are the same as C variables _emx_rev and _emx_vprt).
+ Variable $OS2::emx_env implemented (same as C variable _emx_env).
+ Variable $OS2::os_ver implemented (_osmajor + 0.001 * _osminor).
+
+ Improved centralized management of HAB and HMQ. To get Perl's
+ HAB, call perl_hab_GET(). (After the initial call one
+ can use Perl_hab instead.) To require Perl's HMQ,
+ call perl_hmq_GET(), to release it call perl_hmq_UNSET(),
+ to obtain it between these calls use Perl_hmq.
+ HMQ management is refcounted, and the program will morph
+ itself into/from PM if required.
+ If perl.h cannot be included, hab may be obtained by Perl_hab_GET().
+
+ New function OS2::Error(do_harderror,do_exception). Returns
+ undef if it was not called yet, otherwise bit 1 is
+ set if on previous call do_harderror was enabled, bit
+ 2 is set if if on previous call do_exception was enabled.
+ This function enables/disables error popups associated with
+ hardware errors (Disk not ready etc.) and software exceptions.
+
+ New function OS2::Errors2Drive(drive). Returns undef if it was
+ not called yet, otherwise return false if Errors were
+ not requested to be written to a hard drive, or the
+ drive letter if this was requested.
+ This function may redirect error popups associated with
+ hardware errors (Disk not ready etc.) and software exceptions
+ to the file POPUPLOG.OS2 at the root directory of the
+ specified drive. Overrides OS2::Error() specified by
+ individual programs. Given argument undef will
+ disable redirection. Has global effect, persists
+ after the application exits.
+
+ New function OS2::SysInfo(). Returns a hash with system information.
+ The keys of the hash are
+
+ MAX_PATH_LENGTH, MAX_TEXT_SESSIONS, MAX_PM_SESSIONS,
+ MAX_VDM_SESSIONS, BOOT_DRIVE, DYN_PRI_VARIATION,
+ MAX_WAIT, MIN_SLICE, MAX_SLICE, PAGE_SIZE,
+ VERSION_MAJOR, VERSION_MINOR, VERSION_REVISION,
+ MS_COUNT, TIME_LOW, TIME_HIGH, TOTPHYSMEM, TOTRESMEM,
+ TOTAVAILMEM, MAXPRMEM, MAXSHMEM, TIMER_INTERVAL,
+ MAX_COMP_LENGTH, FOREGROUND_FS_SESSION,
+ FOREGROUND_PROCESS
+
+ New function OS2::BootDrive(force). Returns a letter without colon.
+
+ New functions OS2::MorphPM(serve)/OS2::UnMorphPM(serve). Transforms
+ the current application into a PM application and back.
+ The argument true means that a real message loop is
+ going to be performed.
+ OS2::MorphPM() returns the PM message queue handle as an integer.
+
+ New function OS2::Serve_Messages(force). Fake on-demand
+ retrieval of outstanding PM messages. If force is false,
+ will not dispatch messages if a real message loop is known to
+ be present. Returns number of messages retrieved.
+ Dies with "QUITing..." if WM_QUIT message is obtained.
+
+ New function OS2::Process_Messages(force [, cnt]). Retrieval
+ of PM messages until window creation/destruction.
+ If force is false, will not dispatch messages
+ if a real message loop is known to be present.
+ Returns change in number of windows. If cnt is given,
+ it is incremented by the number of messages retrieved.
+ Dies with "QUITing..." if WM_QUIT message is obtained.
+