Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Where does the line</p> <pre><code>f = reinterpret_cast&lt;void(*)(int*)&gt;(dlsym(RTLD_DEFAULT, "real_f.symbol_name_")); </code></pre> <p>occur in <code>test.cc</code>? The pointer will be initialized when the line is executed (which of course depends on when the function which contains it is called). Or did you mean to write</p> <pre><code>void (*f)(int* ) = reinterpret_cast&lt;void(*)(int*&gt;(dlsym(RTLD_DEFAULT, "real_f.symbol_name_"); </code></pre> <p>? In this case, the pointer will be initialized during static initialization. Which means that you still have order of initialization issues if you try to use the pointers in the constructor of a static object.</p> <p>The classical solution for this would be to use some sort of singleton:</p> <pre><code>struct LibraryPointers { void (*f)(int* ); // ... static LibraryPointers const&amp; instance() private: LibraryPointers(); }; LibraryPointers const&amp; LibraryPointers::instance() { static LibraryPointers theOneAndOnly; return theOneAndOnly; } LibraryPointers::LibraryPointers() : f( reinterpret_cast&lt;void(*)(int*)&gt;(dlsym(RTLD_DEFAULT, "real_f.symbol_name_")) ) , // initialization of other pointers... { } </code></pre> <p>Then wrap the library in a C++ class which uses this structure to get the addresses of the pointers.</p> <p>And one last remark: the <code>reinterpret_cast</code> you are trying to do isn't legal, at least not formally. (I think that both Sun CC and g++ will accept it, however.) According to Posix, the correct way to get a pointer to function from <code>dlsym</code> would be:</p> <pre><code>void (*f)(int* ); *reinterpret_cast&lt;void**&gt;(&amp;f) = dlsym(...); </code></pre> <p>This doesn't lend itself to initializations, however.</p>
    singulars
    1. This table or related slice is empty.
    1. POPopulate global function pointers in shared library (Solaris, Sun Studio)
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USJames Kanze
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POPopulate global function pointers in shared library (Solaris, Sun Studio)
      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. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COYes, thank you, I indeed meant to write it as you said. I will correct the question. I know that I will have problems with other static objects in the same library, but is that also true in other libraries that use this library?
      singulars
      1. PO
      1. USlytenyn
    2. COI would really like to avoid the singleton solution, I had thought of this also..
      singulars
      1. PO
      1. USlytenyn
    3. CO@lytenyn Other libraries shouldn't have a problem **if** they are loaded after your library has been loaded. (And of course, if they are loaded before, the global symbol with the pointer to the function isn't available.)
      singulars
      1. PO
      1. USJames Kanze
 

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