http://www.newlc.com/en/topic-10069 Comments for "Shouldn't TPtr have a default constructor if it encapsulate a pointer?" en http://www.newlc.com/en/topic-10069#comment-24246 <div class="smf-content">Controls your use of the pointer -&nbsp; it&#039;s only meant to be used to deal with existing blocks of data.<br /><br />Consider TPtrC, it does have a default constructor, however this class only allows you to read data. TPtrC&#039;s default constructor set&#039;s it&#039;s self to NULL, and length 0. So since your only use of a TPtrC will be read data, if you attempted to read some information from a TPtrC you&#039;d end up with a descriptor of NULL content and zero length. - This makes sense.<br /><br />Now consider TPtr, it&#039;s mean to be used for looking at, and modifying data... if it had a default constructor what would it set it&#039;s self too ? NULL and 0 length ? - Ok, but now what happens when you try to write to this descriptor.... you&#039;d get a memory exception, and your app would panic and die - probably with an unhandled exception.<br /><br />To prevent this, TPtr does not have a default constructor, so you have to set it to something before you can use it.</div> Thu, 25 Aug 2005 19:29:08 +0200 mc_woods comment 24246 at http://www.newlc.com http://www.newlc.com/en/topic-10069 <div class="smf-content"></div><p><a href="http://www.newlc.com/en/topic-10069">read more</a></p> http://www.newlc.com/en/topic-10069#comments Symbian C++ Thu, 25 Aug 2005 19:09:43 +0200 nikolas 10487 at http://www.newlc.com