How to pass an error pointer in the Swift language?
SwiftSwift Problem Overview
I am attempting to pass an error pointer in swift and am unable to do so. The compiler complains that "NSError is not convertible to 'NSErrorPointer'".
var error: NSError = NSError()
var results = context.executeFetchRequest(request, error: error)
if(error != nil)
{
println("Error executing request for entity \(entity)")
}
Swift Solutions
Solution 1 - Swift
You just pass a reference like so:
var error: NSError?
var results = context.executeFetchRequest(request, error: &error)
if error != nil {
println("Error executing request for entity \(entity)")
}
Two important points here:
NSError?
is an optional (and initialized tonil
)- you pass by reference using the
&
operator (e.g.,&error
)
Solution 2 - Swift
This suggestion is up for discussion, but some engineers would prefer to use the golden path syntax:
var maybeError: NSError?
if let results = context.executeFetchRequest(request, error: &maybeError) {
// Work with results
} else if let error = maybeError {
// Handle the error
}