How to fix C-style for statement?

Question

What is right way to fix C-style for statement for the code which is posted below?

Currently I am getting this warring:

C-style for statement is deprecated and will be removed in a future version of Swift

var ifaddr : UnsafeMutablePointer<ifaddrs> = nil
if getifaddrs(&ifaddr) == 0 {
    // Warning
    for (var ptr = ifaddr; ptr != nil; ptr = ptr.memory.ifa_next) {
        // Do some stuff...
    }
}

Hey Ramis did my answer help you? Please let me know if you have any other questions. — JAL, Mar 23 '16 at 19:47
@JAL Sorry, but I did not have chance to try it as I am busy with other issues. — Ramis, Mar 24 '16 at 05:58

score 7 · Accepted Answer · answered Mar 22 '16 at 13:50

7

You could convert the for loop into a while loop:

var ptr = ifaddr
while ptr != nil {
    // Do stuff
    ptr = ptr.memory.ifa_next
}

answered Mar 22 '16 at 13:50

JAL

41,701
23
172
300

score 3 · Answer 2 · answered Mar 31 '16 at 12:23

3

Here's a version that worked for me.

var ptr = ifaddr
repeat {
   ptr = ptr.memory.ifa_next
   if ptr != nil {
      ...
   }
} while ptr != nil

answered Mar 31 '16 at 12:23

Telstar

143
8

score 0 · Answer 3 · answered Oct 07 '16 at 19:45

As of Swift 3 you can use sequence for generalized loops, such as traversing a "linked list". Here:

var ifaddr : UnsafeMutablePointer<ifaddrs>?
if getifaddrs(&ifaddr) == 0 {
    if let firstAddr = ifaddr {
        for ptr in sequence(first: firstAddr, next: { $0.pointee.ifa_next }) {
            // ...
        }
    }
    freeifaddrs(ifaddr)
}

How to fix C-style for statement?

3 Answers3

Linked