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ExtUtils::XSSymSet(3pm)               Perl Programmers Reference Guide               ExtUtils::XSSymSet(3pm)



NAME
       ExtUtils::XSSymSet - keep sets of symbol names palatable to the VMS linker

SYNOPSIS
         use ExtUtils::XSSymSet;

         $set = new ExtUtils::XSSymSet;
         while ($sym = make_symbol()) { $set->addsym($sym); }
         foreach $safesym ($set->all_trimmed) {
           print "Processing $safesym (derived from ",$self->get_orig($safesym),")\n";
           do_stuff($safesym);
         }

         $safesym = ExtUtils::XSSymSet->trimsym($onesym);

DESCRIPTION
       Since the VMS linker distinguishes symbols based only on the first 31 characters of their names, it
       is occasionally necessary to shorten symbol names in order to avoid collisions.  (This is especially
       true of names generated by xsubpp, since prefixes generated by nested package names can become quite
       long.)  "ExtUtils::XSSymSet" provides functions to shorten names in a consistent fashion, and to
       track a set of names to insure that each is unique.  While designed with xsubpp in mind, it may be
       used with any set of strings.

       This package supplies the following functions, all of which should be called as methods.

       new([$maxlen[,$silent]])
           Creates an empty "ExtUtils::XSSymset" set of symbols.  This function may be called as a static
           method or via an existing object.  If $maxlen or $silent are specified, they are used as the
           defaults for maximum name length and warning behavior in future calls to addsym() or trimsym()
           via this object.  If the compiler has been instructed to do its own symbol shortening via
           $Config{'useshortenedsymbols'}, a value of 2048 is assumed for $maxlen as a way of bypassing the
           shortening done by this module.

       addsym($name[,$maxlen[,$silent]])
           Creates a symbol name from $name, using the methods described under trimsym(), which is unique in
           this set of symbols, and returns the new name.  $name and its resultant are added to the set, and
           any future calls to addsym() specifying the same $name will return the same result, regardless of
           the value of $maxlen specified.  Unless $silent is true, warnings are output if $name had to be
           trimmed or changed in order to avoid collision with an existing symbol name.  $maxlen and $silent
           default to the values specified when this set of symbols was created.  This method must be called
           via an existing object.

       trimsym($name[,$maxlen[,$silent]])
           Creates a symbol name $maxlen or fewer characters long from $name and returns it. If $name is too
           long, it first tries to shorten it by removing duplicate characters, then by periodically
           removing non-underscore characters, and finally, if necessary, by periodically removing
           characters of any type.  $maxlen defaults to 31.  Unless $silent is true, a warning is output if
           $name is altered in any way.  This function may be called either as a static method or via an
           existing object, but in the latter case no check is made to insure that the resulting name is
           unique in the set of symbols.    If the compiler has been instructed to do its own symbol
           shortening via $Config{'useshortenedsymbols'}, a value of 2048 is assumed for $maxlen as a way of
           bypassing the shortening done by this module.

       delsym($name)
           Removes $name from the set of symbols, where $name is the original symbol name passed previously
           to addsym().  If $name existed in the set of symbols, returns its "trimmed" equivalent, otherwise
           returns "undef".  This method must be called via an existing object.

       get_orig($trimmed)
           Returns the original name which was trimmed to $trimmed by a previous call to addsym(), or
           "undef" if $trimmed does not correspond to a member of this set of symbols.  This method must be
           called via an existing object.

       get_trimmed($name)
           Returns the trimmed name which was generated from $name by a previous call to addsym(), or
           "undef" if $name is not a member of this set of symbols.  This method must be called via an
           existing object.

       all_orig()
           Returns a list containing all of the original symbol names from this set.

       all_trimmed()
           Returns a list containing all of the trimmed symbol names from this set.

AUTHOR
       Charles Bailey  <bailey@newman.upenn.edu>

REVISION
       Last revised 8-Oct-2010, for Perl 5.13.6.



perl v5.16.2                                     2012-10-11                          ExtUtils::XSSymSet(3pm)