OK, only a shot in the dark after playing with B::Concise and B::Deparse but here goes . . .
In the first and third cases the reference is to a readonly PV value. This is copied directly into the SV slot of *a and when you try and modify it you get the error.
In the middle case either a non-readonly copy of the PV is pushed onto the stack, or the make-reference-to-list opcode (refgen I think) makes a non-readonly copy. Whichever case it is, the PV that's stuck in the SV slot of *a is mutable.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|