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NAME

     Devel::SelfStubber - generate stubs for a SelfLoading module



SYNOPSIS
     To generate just the stubs:

         use Devel::SelfStubber;
         Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');

     or to generate the whole module with stubs inserted
     correctly

         use Devel::SelfStubber;
         $Devel::SelfStubber::JUST_STUBS=0;
         Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');

     MODULENAME is the Perl module name, e.g. Devel::SelfStubber,
     NOT 'Devel/SelfStubber' or 'Devel/SelfStubber.pm'.

     MY_LIB_DIR defaults to '.' if not present.



DESCRIPTION
     Devel::SelfStubber prints the stubs you need to put in the
     module before the __DATA__ token (or you can get it to print
     the entire module with stubs correctly placed). The stubs
     ensure that if a method is called, it will get loaded. They
     are needed specifically for inherited autoloaded methods.

     This is best explained using the following example:

     Assume four classes, A,B,C & D.

     A is the root class, B is a subclass of A, C is a subclass
     of B, and D is another subclass of A.

                             A
                            / \
                           B   D
                          /
                         C

     If D calls an autoloaded method 'foo' which is defined in
     class A, then the method is loaded into class A, then
     executed. If C then calls method 'foo', and that method was
     reimplemented in class B, but set to be autoloaded, then the
     lookup mechanism never gets to the AUTOLOAD mechanism in B
     because it first finds the method already loaded in A, and
     so erroneously uses that. If the method foo had been stubbed
     in B, then the lookup mechanism would have found the stub,
     and correctly loaded and used the sub from B.


     So, for classes and subclasses to have inheritance correctly
     work with autoloading, you need to ensure stubs are loaded.

     The SelfLoader can load stubs automatically at module
     initialization with the statement 'SelfLoader-
     >load_stubs()';, but you may wish to avoid having the stub
     loading overhead associated with your initialization (though
     note that the SelfLoader::load_stubs method will be called
     sooner or later - at latest when the first sub is being
     autoloaded). In this case, you can put the sub stubs before
     the __DATA__ token. This can be done manually, but this
     module allows automatic generation of the stubs.

     By default it just prints the stubs, but you can set the
     global $Devel::SelfStubber::JUST_STUBS to 0 and it will
     print out the entire module with the stubs positioned
     correctly.

     At the very least, this is useful to see what the SelfLoader
     thinks are stubs - in order to ensure future versions of the
     SelfStubber remain in step with the SelfLoader, the
     SelfStubber actually uses the SelfLoader to determine which
     stubs are needed.









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Created 1996-2024 by Maxim Chirkov

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