[MacRuby] #1340: Troubles casting a Pointer from void* to something useful

[MacRuby]

#1340: Troubles casting a Pointer from void* to something useful
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 Reporter:  mrada@…                 |       Owner:  lsansonetti@…        
     Type:  defect                  |      Status:  new                  
 Priority:  blocker                 |   Milestone:                       
Component:  MacRuby                 |    Keywords:                       
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 I've got an odd behavior where I am given a void* from a function, and I
 try to cast it into something useful, but cannot.

 The documentation for the function says I should be given a CFStringRef,
 and so I cast it and try to access it, but it looks like it is jumping
 right into the data structure. I cannot call CFString functions on the
 pointer, or first index.

 If I try #[1], it will segfault, I think trying to figure out what the
 object is (generated from the example code further down):

 {{{
 0   libobjc.A.dylib                     0x00007fff8200a3e6 object_getClass
 + 11
 1   miniruby                            0x00000001000deaa4
 rb_objc_convert_immediate + 36 (objc.m:570)
 2   miniruby                            0x000000010013beb9 rb_vm_dispatch
 + 9177 (dispatcher.cpp:161)
 }}}

 Example code:
 {{{
 framework 'Cocoa'

 current_keyboard = TISCopyCurrentKeyboardInputSource()
 name = TISGetInputSourceProperty(current_keyboard,
 KTISPropertyLocalizedName)

 p name[0]
 p name.type

 name.cast!('^{__CFString}')
 p name[0] # => NSCFString
 p name[1] # segfault
 CFStringGetLength(name) # => segfault
 CFStringGetLength(name[0]) # => uncaught objective-c exception

 name.cast!('@')
 p name[0] # => NSCFString
 p name[1] # segfault
 CFStringGetLength(name) # => segfault
 CFStringGetLength(name[0]) # => uncaught objective-c exception
 }}}

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/1340>
MacRuby <http://macruby.org/>