Databases
StackOverflow2013
Postsdbo
POdeterming calling object when working with dlopen() objects
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POdeterming calling object when working with dlopen() objects
    primarykey
    data
    text
    <p>I'm writing a (C) program which utilizes a plugin system via dlopen(). The stumbling block I'm running across is that the main program exports a few functions which really need to know the plugin that called them (mostly record keeping, and so a plugin can be unloaded properly as they add things like function pointers to the main program).</p> <p>I cant seem to find a clean way to do this. The options I've come up with so far:</p> <ol> <li>require the plugin to provide its name, or some data I give it on load as an argument to the functions.<br> <ul> <li>I dont like this option because not all functions care who they were called from, so it makes it inconsistent and messy. Plus I would like to make it as difficult as possible for the plugin to lie about who it is</li> </ul></li> <li>Use backtrace() to determine the object name of the previous function. <ul> <li>This just seems fairly ugly and non-portable.</li> </ul></li> <li>Require the plugin to put a file-level struct (or other variable) containing its name (lets call it 'plugin_info' for discussion). Then use dlsym() when loading the plugin to look up the variable and index it (like in a hash) by its name. Then put in #define macros which the plugins use to call the functions and have the macro add <code>&amp;plugin_info</code> as an argument. <ul> <li>This is what I'm using now but it seems hackish. For one you have to have the macro pass '&amp;plugin_info', if you just pass 'plugin_info' then it pulls the 'plugin_info' from the main program, not the plugin. Referencing it by address seems to make it so that its compiled with the correct one, and that it doesnt get relocated. That makes me dislike this option as that seems like its undefined behavior, however it does work. Also the macros can make it a bit confusing when the plugin developer has a problem with the function call (passing wrong argument type or whatnot).</li> </ul></li> </ol> <p>If there's any other ideas or techniques, I would love to love to know.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USPatrick
    1. USPatrick
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POdeterming calling object when working with dlopen() objects
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POdeterming calling object when working with dlopen() objects
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POdeterming calling object when working with dlopen() objects
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO+1 well-written question with detailed explanation of what options you've evaluated/tried and what you're looking for.
      singulars
      1. POdeterming calling object when working with dlopen() objects
      1. USR..
 

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