Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>There isn't room in comments to answer your question in the comment well, so I'll put it in another answer.</p> <p>Any time your code gets an NPObject from a NPObject function (one of those you mentioned above), you should Release that NPObject when you're done with it. (that could be immediately, or you could save it for awhile and release it when your object gets destroyed). The same holds true with a NPVariant. It does <em>not</em> hold true with the arguments passed into your Invoke function, but the return value you set will get released by the browser when it's done.</p> <p>When you call NPN_GetValue and get an NPObject from there, that also has to be released. This means that when the browser calls NPP_GetValue, it will release your NPObject when it's done. If you want to create a new NPObject every time the browser calls NPP_GetValue to get your NPObject, then you don't have to call NPN_RetainObject on it; the assumption in the NPAPI example is that you are saving a copy of your NPObject so that it doesn't get deleted until your plugin object gets deleted.</p> <p>Since the browser will call Release for every time that it calls NPP_GetValue to get your NPObject, you need to make sure that the refcount is incremented before you return it. The reason you don't have to call it twice in the case that you're going to keep it is that NPN_CreateObject does an implicit Retain before it returns your object.</p> <p>I have written up a more detailed explanation here:</p> <ul> <li><a href="http://colonelpanic.net/2009/12/memory-management-in-npapi" rel="nofollow noreferrer">http://colonelpanic.net/2009/12/memory-management-in-npapi</a></li> </ul>
    singulars
    1. This table or related slice is empty.
    1. POwhen to release object in npapi plugin
      singulars
      1. PTQuestion
    1. PTAnswer
    1. UStaxilian
    1. UStaxilian
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POwhen to release object in npapi plugin
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COthanks. I think I finally get it. Correct me if I am wrong. For example: if you get an object A by NPN_Evaluate, and then set it to another object B through NPN_SetProperty(npp, B, identifier, A), you still have to and can NPN_ReleaseVariableValue(A) immediately (you destroy what you created). But you don't have to worry that B will get seg fault when it tried to access property A because browser inc ref count of A in NPN_SetProperty. Final word, that is the way browser implemented nested release.
      singulars
      1. PO
      1. USliuliu
    2. COI'm not sure if I fully understand what you're saying. If you get an object A that is an NPVariant, then yes, you need to release it, but not until you're done with it. Once you release, you must assume that it is no longer accessible to you. And yes, if it is implemented properly, B should have incremented the reference count during SetProperty if it holds onto a reference. Any time you get a reference, retain; any time you're done with one, release. I wrote up a blog post on the subject with a little more detail: http://colonelpanic.net/2009/12/memory-management-in-npapi/
      singulars
      1. PO
      1. UStaxilian
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload