Thanks for the pointers. Good reading, but I'm still confused. I think
that the first issue is clear to me now, but I don't know what I have to
do to make the closure be seen as satisfying the type of the function
pointer. It worked in Swift 2.2 as
XML_SetEndElementHandler(parser) { (userData:
UnsafeMutablePointer<Void>, name: UnsafePointer<XML_Char>) -> Void in
All that's changed is making the UnsafeMutablePointer<Void> into
UnsafeMutableRawPointer, unless it's the unwrapped nature of the
parameter in the error message:
Cannot convert value of type '(UnsafeMutableRawPointer,
UnsafePointer<XML_Char>) -> Void' to expected argument type
'XML_EndElementHandler!'
I don't know what I need to do next. Any help is much appreciated.
Quinn "The Eskimo!" via swift-users <mailto:swift-users@swift.org>
28 September 2016 at 11:26
I recommend reading the whole “Migrating to Swift 2.3 or Swift 3 from
Swift 2.2” doc, but for this specific issue you should start with the
“UnsafeRawPointer Migration” doc that it links to.
<https://swift.org/migration-guide/>
<https://swift.org/migration-guide/se-0107-migrate.html>
Share and Enjoy
--
Quinn "The Eskimo!" <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
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John Brownie <mailto:john_brow...@sil.org>
28 September 2016 at 9:29
I have a Swift wrapper for the expat XML parser, and I just went
through the update to Swift 3, and I'm thrown a series of errors that
mostly appear to be of two types. Here is a representative function of
the first type:
func parse() throws {
var done = false
while !done {
let buffer: UnsafeMutablePointer<Void> =
XML_GetBuffer(parser, Int32(bufsize))
if buffer == nil {
let errorCode = XML_GetErrorCode(parser)
throw ExpatError(reason: "Error \(errorCode),
\(XML_ErrorString(errorCode))")
}
let bytesRead =
readData(UnsafeMutablePointer<UInt8>(buffer), bufferLength: bufsize)
done = bytesRead < bufsize
if XML_ParseBuffer(parser, Int32(bytesRead), Int32(done ?
1 : 0)) != XML_STATUS_OK {
let errorCode = XML_GetErrorCode(parser)
throw ExpatError(reason: "Error \(errorCode),
\(XML_ErrorString(errorCode))")
}
}
}
Xcode 8's migrator changed the declaration of buffer to
UnsafeMutableRawPointer?, but the readData call gives an error:
Cannot invoke initializer for type 'UnsafeMutablePointer<UInt8>' with
an argument list of type '(UnsafeMutableRawPointer?)'
Pointer conversion restricted: use '.assumingMemoryBound(to:)' or
'.bindMemory(to:capacity:)' to view memory as a type.
Overloads for 'UnsafeMutablePointer<UInt8>' exist with these partially
matching parameter lists: (RawPointer), (OpaquePointer),
(OpaquePointer?), (UnsafeMutablePointer<Pointee>),
(UnsafeMutablePointer<Pointee>?)
Where can I read up on how to make the conversion? My initial effort is:
let bytesRead = readData(buffer!.bindMemory(to:
UInt8.self, capacity: bufsize), bufferLength: bufsize)
That's more or less thrashing around with no real understanding.
The second type is turning a closure into the appropriate C function
pointer. For example:
XML_SetEndElementHandler(parser) { (userData:
UnsafeMutableRawPointer, name: UnsafePointer<XML_Char>) -> Void in
let theParser = unsafeBitCast(userData, to:
ExpatSwift.self)
let theName = ExpatSwift.getString(name)
theParser.endElement(theName)
}
This gets an error:
Cannot convert value of type '(UnsafeMutableRawPointer,
UnsafePointer<XML_Char>) -> Void' to expected argument type
'XML_EndElementHandler!'
XML_EndElementHandler is defined as:
typedef void (XMLCALL *XML_EndElementHandler) (void *userData,
const XML_Char *name);
Here I have no real clue as to how to fix it.
So, any pointers to either how to fix these problems or to a good
source to read to understand them?
John
--
John Brownie
In Finland on furlough from SIL Papua New Guinea
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