Swift example of C libproc API

libproc_example.swift

import Darwin

// Call proc_listallpids once with nil/0 args to get the current number of pids
let initialNumPids = proc_listallpids(nil, 0)

// Allocate a buffer of these number of pids.
// Make sure to deallocate it as this class does not manage memory for us.
let buffer = UnsafeMutablePointer<pid_t>.allocate(capacity: Int(initialNumPids))
defer {
    buffer.deallocate()
}

// Calculate the buffer's total length in bytes
let bufferLength = initialNumPids * Int32(MemoryLayout<pid_t>.size)

// Call the function again with our inputs now ready
let numPids = proc_listallpids(buffer, bufferLength)

// Loop through each pid
for i in 0..<numPids {
    
    // Print the current pid
    let pid = buffer[Int(i)]
    print("[\(i)] \(pid)")
    
    // Allocate a buffer to store the name
    let nameBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: Int(MAXPATHLEN))
    defer {
        nameBuffer.deallocate()
    }
    
    // Now get and print the name. Not all processes return a name here...
    let nameLength = proc_name(pid, nameBuffer, UInt32(MAXPATHLEN))
    if nameLength > 0 {
        let name = String(cString: nameBuffer)
        print("  name=\(name)")
    }
    
    // ...so also get the process' path
    let pathBuffer = UnsafeMutablePointer<UInt8>.allocate(capacity: Int(MAXPATHLEN))
    defer {
        pathBuffer.deallocate()
    }
    let pathLength = proc_pidpath(pid, pathBuffer, UInt32(MAXPATHLEN))
    if pathLength > 0 {
        let path = String(cString: pathBuffer)
        print("  path=\(path)")
    }
}