Databases
StackOverflow2013
Postsdbo
POObjective-C va_list and selectors
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POObjective-C va_list and selectors
    primarykey
    data
    text
    <p>Is it possible to use <code>@selector</code> and <code>performSelector:</code> (or similar) with methods using variable arguments list?</p> <p>I'm writing a class that can be assigned a delegate to override the default behavior. In the presence of a delegate select method calls made on an instance of that class will be forward to the same corresponding delegate method, some which use variable argument lists.</p> <p>So, for instance, I need to be able to create retrieve <code>SEL</code> reference and message the delegate object with a method such as this:</p> <pre><code>- (void)logEventWithFormat:(NSString *)format, ... { va_list argList; id del = self.delegate; if (del != nil &amp;&amp; [del conformsToProtocol:@protocol(AProtocolWithOptionalMethods)] &amp;&amp; [del respondsToSelector:@selector(logEventWithFormat:)]) { // Perform selector on object 'del' with 'argList' } } </code></pre> <p>I am assuming this is not possible, hence the similar method declaration in the Foundation framework - in <code>NSString</code>:</p> <pre><code>- (id)initWithFormat:(NSString*)format, ...; </code></pre> <p>and </p> <pre><code>- (id)initWithFormat:(NSString *)format arguments:(va_list)argList; </code></pre> <p>I assume that the protocol I wish to delegate to should suggest the implementation of:</p> <pre><code>- (void)logEventWithFormat:(NSString *)format arguments:(va_list)argList; </code></pre> <p>so I the selector <code>@selector(logEventWithFormat:arguments:)</code> can be used an called with:</p> <pre><code>[del performSelector:@selector(logEventWithFormat:arguments:) withObject:format withObject:argList]; </code></pre> <p>I just wondered if I was missing something or going the long way around to achieve what I'm trying to?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USpryomoax
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POObjective-C va_list and selectors
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POObjective-C va_list and selectors
      1. USgriotspeak
      1. VTFavorite
    3. VO
      singulars
      1. POObjective-C va_list and selectors
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

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