[MacRuby] #1160: Need ability to access errno from Ruby code

[MacRuby]

#1160: Need ability to access errno from Ruby code
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 Reporter:  warpflyght@…              |        Owner:  lsansonetti@…        
     Type:  enhancement               |       Status:  closed               
 Priority:  minor                     |    Milestone:  MacRuby 0.9          
Component:  MacRuby                   |   Resolution:  fixed                
 Keywords:                            |  
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Comment(by warpflyght@…):

 Using BridgeSupport. I've added custom BridgeSupport definitions in a
 couple of tools now. In the case of openpty(3), I don't need to set the
 termios or winsize structs, so the XML looks like this:

 {{{
 <?xml version='1.0'?>
 <!DOCTYPE signatures SYSTEM
 "file://localhost/System/Library/DTDs/BridgeSupport.dtd">
 <signatures version='0.9'>
   <function name='openpty'>
     <arg type='^i' type_modifier='o'/>
     <arg type='^i' type_modifier='o'/>
     <arg type='*' type_modifier='o'/>
     <arg type='^v'/> <!-- ignored -->
     <arg type='^v'/> <!-- ignored -->
     <reval type='i'/>
   </function>
 </signatures>
 }}}

 And the code to call it should look like this (untested):

 {{{
 load_bridge_support_file "/path/to/custom_file.bridgesupport"

 # Allocate space for file descriptors
 master_fd = Pointer.new(:int)
 slave_fd = pointer.new(:int)

 # Call openpty(3) to get descriptors back
 result = openpty(master, slave, nil, nil, nil)
 raise SystemCallError.new(Errno.code) unless result == 0

 # Use IO.for_fd to wrap file descriptors
 # From here, treat like a pipe: fork, close appropriate ends, and hook up
 to stdin/stdout/stderr
 }}}

 I've used this technique to call various C functions with RubyCocoa (using
 a custom BridgeSupport file) and Ruby/DL (chanting the appropriate
 incantations), but not with MacRuby.

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/1160#comment:5>
MacRuby <http://macruby.org/>