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README.tru64 - Perl version 5 on Tru64 (formerly known as Digital UNIX formerly known as DEC OSF/1) systems


This document describes various features of HP's (formerly Compaq's, formerly Digital's) Unix operating system (Tru64) that will affect how Perl version 5 (hereafter just Perl) is configured, compiled and/or runs.

Compiling Perl 5 on Tru64

The recommended compiler to use in Tru64 is the native C compiler. The native compiler produces much faster code (the speed difference is noticeable: several dozen percentages) and also more correct code: if you are considering using the GNU C compiler you should use at the very least the release of 2.95.3 since all older gcc releases are known to produce broken code when compiling Perl. One manifestation of this brokenness is the lib/sdbm test dumping core; another is many of the op/regexp and op/pat, or ext/Storable tests dumping core (the exact pattern of failures depending on the GCC release and optimization flags).

Using Large Files with Perl on Tru64

In Tru64 Perl is automatically able to use large files, that is, files larger than 2 gigabytes, there is no need to use the Configure -Duselargefiles option as described in INSTALL (though using the option is harmless).

Threaded Perl on Tru64

If you want to use threads, you should primarily use the new Perl 5.8.0 threads model by running Configure with -Duseithreads.

The old Perl 5.005 threads is obsolete, unmaintained, and its use is discouraged. If you really want it, run Configure with the -Dusethreads -Duse5005threads options as described in INSTALL.

Either thread model is going to work only in Tru64 4.0 and newer releases, older operating releases like 3.2 aren't probably going to work properly with threads.

Long Doubles on Tru64

You cannot Configure Perl to use long doubles unless you have at least Tru64 V5.0, the long double support simply wasn't functional enough before that. Perl's Configure will override attempts to use the long doubles (you can notice this by Configure finding out that the modfl() function does not work as it should).

At the time of this writing (June 2002), there is a known bug in the Tru64 libc printing of long doubles when not using "e" notation. The values are correct and usable, but you only get a limited number of digits displayed unless you force the issue by using printf "%.33e",$num or the like. For Tru64 versions V5.0A through V5.1A, a patch is expected sometime after perl 5.8.0 is released. If your libc has not yet been patched, you'll get a warning from Configure when selecting long doubles.

64-bit Perl on Tru64

In Tru64 Perl's integers are automatically 64-bit wide, there is no need to use the Configure -Duse64bitint option as described in INSTALL. Similarly, there is no need for -Duse64bitall since pointers are automatically 64-bit wide.

Warnings about floating-point overflow when compiling Perl on Tru64

When compiling Perl in Tru64 you may (depending on the compiler release) see two warnings like this

    cc: Warning: numeric.c, line 104: In this statement, floating-point overflow occurs in evaluating the expression "1.8e308". (floatoverfl)
        return HUGE_VAL;

and when compiling the POSIX extension

    cc: Warning:, line 2007: In this statement, floating-point overflow occurs in evaluating the expression "1.8e308". (floatoverfl)
                return HUGE_VAL;

The exact line numbers may vary between Perl releases. The warnings are benign and can be ignored: in later C compiler releases the warnings should be gone.

When the file pp_sys.c is being compiled you may (depending on the operating system release) see an additional compiler flag being used: -DNO_EFF_ONLY_OK. This is normal and refers to a feature that is relevant only if you use the filetest pragma. In older releases of the operating system the feature was broken and the NO_EFF_ONLY_OK instructs Perl not to use the feature.

Testing Perl on Tru64

During "make test" the comp/cpp will be skipped because on Tru64 it cannot be tested before Perl has been installed. The test refers to the use of the -P option of Perl.

ext/ODBM_File/odbm Test Failing With Static Builds

The ext/ODBM_File/odbm is known to fail with static builds (Configure -Uusedl) due to a known bug in Tru64's static libdbm library. The good news is that you very probably don't need to ever use the ODBM_File extension since more advanced NDBM_File works fine, not to mention the even more advanced DB_File.

Perl Fails Because Of Unresolved Symbol sockatmark

If you get an error like

    Can't load '.../OSF1/lib/perl5/5.8.0/alpha-dec_osf/auto/IO/' for module IO: Unresolved symbol in .../lib/perl5/5.8.0/alpha-dec_osf/auto/IO/ sockatmark at .../lib/perl5/5.8.0/alpha-dec_osf/ line 75.  

you need to either recompile your Perl in Tru64 4.0D or upgrade your Tru64 4.0D to at least 4.0F: the sockatmark() system call was added in Tru64 4.0F, and the IO extension refers that symbol.


Jarkko Hietaniemi <>




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