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<dd>
<p>Lightweight and lvalue version of <a href="#item_pad_sv"><code>PAD_SV</code></a>.
Get or set the value at offset <code>po</code> in the current pad.
Unlike <a href="#item_pad_sv"><code>PAD_SV</code></a>, does not print diagnostics with -DX.
For internal use only.</p>
</dd>
<dd>
<pre>
        SV *    PAD_SVl(PADOFFSET po)</pre>
</dd>
</li>
<dt><strong><a name="item_saveclearsv">SAVECLEARSV</a></strong>

<dd>
<p>Clear the pointed to pad value on scope exit. (i.e. the runtime action of 'my')</p>
</dd>
<dd>
<pre>
        void    SAVECLEARSV(SV **svp)</pre>
</dd>
</li>
<dt><strong><a name="item_savecomppad">SAVECOMPPAD</a></strong>

<dd>
<p>save PL_comppad and PL_curpad</p>
</dd>
<dd>
<pre>
        void    SAVECOMPPAD()</pre>
</dd>
</li>
<dt><strong><a name="item_savepadsv">SAVEPADSV</a></strong>

<dd>
<p>Save a pad slot (used to restore after an iteration)</p>
</dd>
<dd>
<p><table cellspacing="0" cellpadding="0"><tr><td>XXX DAPM it would make more sense to make the arg a PADOFFSET
<tr><td><td>void<td>SAVEPADSV(PADOFFSET po)</table></p>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="functions_in_file_pp_ctl_c">Functions in file pp_ctl.c</a></h1>
<dl>
<dt><strong><a name="item_find_runcv">find_runcv</a></strong>

<dd>
<p>Locate the CV corresponding to the currently executing sub or eval.
If db_seqp is non_null, skip CVs that are in the DB package and populate
*db_seqp with the cop sequence number at the point that the DB:: code was
entered. (allows debuggers to eval in the scope of the breakpoint rather
than in the scope of the debugger itself).</p>
</dd>
<dd>
<pre>
        CV*     find_runcv(U32 *db_seqp)</pre>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="global_variables">Global Variables</a></h1>
<dl>
<dt><strong><a name="item_pl_dbsingle">PL_DBsingle</a></strong>

<dd>
<p>When Perl is run in debugging mode, with the <strong>-d</strong> switch, this SV is a
boolean which indicates whether subs are being single-stepped.
Single-stepping is automatically turned on after every step.  This is the C
variable which corresponds to Perl's $DB::single variable.  See
<a href="#item_pl_dbsub"><code>PL_DBsub</code></a>.</p>
</dd>
<dd>
<pre>
        SV *    PL_DBsingle</pre>
</dd>
</li>
<dt><strong><a name="item_pl_dbsub">PL_DBsub</a></strong>

<dd>
<p>When Perl is run in debugging mode, with the <strong>-d</strong> switch, this GV contains
the SV which holds the name of the sub being debugged.  This is the C
variable which corresponds to Perl's $DB::sub variable.  See
<a href="#item_pl_dbsingle"><code>PL_DBsingle</code></a>.</p>
</dd>
<dd>
<pre>
        GV *    PL_DBsub</pre>
</dd>
</li>
<dt><strong><a name="item_pl_dbtrace">PL_DBtrace</a></strong>

<dd>
<p>Trace variable used when Perl is run in debugging mode, with the <strong>-d</strong>
switch.  This is the C variable which corresponds to Perl's $DB::trace
variable.  See <a href="#item_pl_dbsingle"><code>PL_DBsingle</code></a>.</p>
</dd>
<dd>
<pre>
        SV *    PL_DBtrace</pre>
</dd>
</li>
<dt><strong><a name="item_pl_dowarn">PL_dowarn</a></strong>

<dd>
<p>The C variable which corresponds to Perl's $^W warning variable.</p>
</dd>
<dd>
<pre>
        bool    PL_dowarn</pre>
</dd>
</li>
<dt><strong><a name="item_pl_last_in_gv">PL_last_in_gv</a></strong>

<dd>
<p>The GV which was last used for a filehandle input operation. (<code>&lt;FH&gt;</code>)</p>
</dd>
<dd>
<pre>
        GV*     PL_last_in_gv</pre>
</dd>
</li>
<dt><strong><a name="item_pl_ofs_sv">PL_ofs_sv</a></strong>

<dd>
<p>The output field separator - <a href="../../lib/Pod/perlvar.html#item___"><code>$,</code></a> in Perl space.</p>
</dd>
<dd>
<pre>
        SV*     PL_ofs_sv</pre>
</dd>
</li>
<dt><strong><a name="item_pl_rs">PL_rs</a></strong>

<dd>
<p>The input record separator - <a href="../../lib/Pod/perlvar.html#item___"><code>$/</code></a> in Perl space.</p>
</dd>
<dd>
<pre>
        SV*     PL_rs</pre>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="gv_functions">GV Functions</a></h1>
<dl>
<dt><strong><a name="item_is_gv_magical">is_gv_magical</a></strong>

<dd>
<p>Returns <code>TRUE</code> if given the name of a magical GV.</p>
</dd>
<dd>
<p>Currently only useful internally when determining if a GV should be
created even in rvalue contexts.</p>
</dd>
<dd>
<p><a href="../../lib/Pod/perlfunc.html#item_flags"><code>flags</code></a> is not used at present but available for future extension to
allow selecting particular classes of magical variable.</p>
</dd>
<dd>
<p>Currently assumes that <code>name</code> is NUL terminated (as well as len being valid).
This assumption is met by all callers within the perl core, which all pass
pointers returned by SvPV.</p>
</dd>
<dd>
<pre>
        bool    is_gv_magical(char *name, STRLEN len, U32 flags)</pre>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="io_functions">IO Functions</a></h1>
<dl>
<dt><strong><a name="item_start_glob">start_glob</a></strong>

<dd>
<p>Function called by <code>do_readline</code> to spawn a glob (or do the glob inside
perl on VMS). This code used to be inline, but now perl uses <code>File::Glob</code>
this glob starter is only used by miniperl during the build process.
Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up.</p>
</dd>
<dd>
<pre>
        PerlIO* start_glob(SV* pattern, IO *io)</pre>
</dd>
</li>
</dl>
<p>
</p>
<hr />
<h1><a name="pad_data_structures">Pad Data Structures</a></h1>
<dl>
<dt><strong><a name="item_cvpadlist">CvPADLIST</a></strong>

<dd>
<p>CV's can have <a href="#item_cvpadlist"><code>CvPADLIST(cv)</code></a> set to point to an AV.</p>
</dd>
<dd>
<p>For these purposes &quot;forms&quot; are a kind-of CV, eval&quot;&quot;s are too (except they're
not callable at will and are always thrown away after the eval&quot;&quot; is done
executing).</p>
</dd>
<dd>
<p>XSUBs don't have CvPADLIST set - dXSTARG fetches values from PL_curpad,
but that is really the callers pad (a slot of which is allocated by
every entersub).</p>
</dd>
<dd>
<p>The CvPADLIST AV has does not have AvREAL set, so REFCNT of component items
is managed &quot;manual&quot; (mostly in pad.c) rather than normal av.c rules.
The items in the AV are not SVs as for a normal AV, but other AVs:</p>
</dd>
<dd>
<p>0'th Entry of the CvPADLIST is an AV which represents the &quot;names&quot; or rather
the &quot;static type information&quot; for lexicals.</p>
</dd>
<dd>
<p>The CvDEPTH'th entry of CvPADLIST AV is an AV which is the stack frame at that
depth of recursion into the CV.
The 0'th slot of a frame AV is an AV which is @_.
other entries are storage for variables and op targets.</p>
</dd>
<dd>
<p>During compilation:
<code>PL_comppad_name</code> is set to the names AV.
<code>PL_comppad</code> is set to the frame AV for the frame CvDEPTH == 1.
<code>PL_curpad</code> is set to the body of the frame AV (i.e. AvARRAY(PL_comppad)).</p>
</dd>
<dd>
<p>During execution, <code>PL_comppad</code> and <code>PL_curpad</code> refer to the live
frame of the currently executing sub.</p>
</dd>
<dd>
<p>Iterating over the names AV iterates over all possible pad
items. Pad slots that are SVs_PADTMP (targets/GVs/constants) end up having
&amp;PL_sv_undef &quot;names&quot; (see pad_alloc()).</p>
</dd>
<dd>
<p>Only my/our variable (SVs_PADMY/SVs_PADOUR) slots get valid names.
The rest are op targets/GVs/constants which are statically allocated
or resolved at compile time.  These don't have names by which they
can be looked up from Perl code at run time through eval&quot;&quot; like
my/our variables can be.  Since they can't be looked up by &quot;name&quot;
but only by their index allocated at compile time (which is usually
in PL_op-&gt;op_targ), wasting a name SV for them doesn't make sense.</p>
</dd>
<dd>
<p>The SVs in the names AV have their PV being the name of the variable.
NV+1..IV inclusive is a range of cop_seq numbers for which the name is
valid.  For typed lexicals name SV is SVt_PVMG and SvSTASH points at the
type.  For <a href="../../lib/Pod/perlfunc.html#item_our"><code>our</code></a> lexicals, the type is SVt_PVGV, and GvSTASH points at the
stash of the associated global (so that duplicate <a href="../../lib/Pod/perlfunc.html#item_our"><code>our</code></a> declarations in the
same package can be detected).  SvCUR is sometimes hijacked to
store the generation number during compilation.</p>
</dd>
<dd>
<p>If SvFAKE is set on the name SV then slot in the frame AVs are
a REFCNT'ed references to a lexical from &quot;outside&quot;. In this case,
the name SV does not have a cop_seq range, since it is in scope
throughout.</p>
</dd>
<dd>
<p>If the 'name' is '&amp;' the corresponding entry in frame AV
is a CV representing a possible closure.
(SvFAKE and name of '&amp;' is not a meaningful combination currently but could
become so if <code>my sub foo {}</code> is implemented.)</p>
</dd>
<dd>
<p>The flag SVf_PADSTALE is cleared on lexicals each time the <a href="../../lib/Pod/perlfunc.html#item_my"><code>my()</code></a> is executed,
and set on scope exit. This allows the 'Variable $x is not available' warning
to be generated in evals, such as</p>
</dd>
<dd>
<pre>
    <span class="operator">{</span> <span class="keyword">my</span> <span class="variable">$x</span> <span class="operator">=</span> <span class="number">1</span><span class="operator">;</span> <span class="keyword">sub</span><span class="variable"> f </span><span class="operator">{</span> <span class="keyword">eval</span> <span class="string">'$x'</span><span class="operator">}</span> <span class="operator">}</span> <span class="variable">f</span><span class="operator">();</span>
</pre>
</dd>
<dd>
<pre>
        AV *    CvPADLIST(CV *cv)</pre>
</dd>
</li>
<dt><strong><a name="item_cv_clone">cv_clone</a></strong>

<dd>
<p>Clone a CV: make a new CV which points to the same code etc, but which
has a newly-created pad built by copying the prototype pad and capturing
any outer lexicals.</p>
</dd>
<dd>
<pre>
        CV*     cv_clone(CV* proto)</pre>
</dd>
</li>
<dt><strong><a name="item_cv_dump">cv_dump</a></strong>

<dd>
<p>dump the contents of a CV</p>
</dd>
<dd>
<pre>
        void    cv_dump(const CV *cv, const char *title)</pre>
</dd>
</li>
<dt><strong><a name="item_do_dump_pad">do_dump_pad</a></strong>

<dd>
<p>Dump the contents of a padlist</p>
</dd>
<dd>
<pre>
        void    do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full)</pre>
</dd>
</li>
<dt><strong><a name="item_intro_my">intro_my</a></strong>

<dd>
<p>&quot;Introduce&quot; my variables to visible status.</p>
</dd>
<dd>