Using dlopen / dlsym to call C functions from Swift

DynamicFunctions.swift

import Darwin

let handle = dlopen("/usr/lib/libc.dylib", RTLD_NOW)
let sym = dlsym(handle, "random")
let functionPointer = UnsafeMutablePointer<() -> CLong>(sym)
let result = functionPointer.memory()

println(result)

This is the actual crash when running the compiled program:

* thread #1: tid = 0x643d, 0x000000010019cde9 libswiftCore.dylib`_swift_retain_(swift::HeapObject*) + 9, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    frame #0: 0x000000010019cde9 libswiftCore.dylib`_swift_retain_(swift::HeapObject*) + 9
libswiftCore.dylib`_swift_retain_(swift::HeapObject*) + 9:
-> 0x10019cde9:  lock   
   0x10019cdea:  addl   $0x4, 0x8(%rdi)
   0x10019cdee:  movq   %rdi, %rax
   0x10019cdf1:  popq   %rbp
(lldb) bt
* thread #1: tid = 0x643d, 0x000000010019cde9 libswiftCore.dylib`_swift_retain_(swift::HeapObject*) + 9, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x000000010019cde9 libswiftCore.dylib`_swift_retain_(swift::HeapObject*) + 9
    frame #1: 0x000000010000199b FunctionPointer`top_level_code + 2459
    frame #2: 0x0000000100001a5a FunctionPointer`main + 42
    frame #3: 0x00007fff8af265c9 libdyld.dylib`start + 1

Hello! Thanks your code.I made it work.

import Darwin

let handle = dlopen("/usr/lib/libc.dylib", RTLD_NOW)
let sym = dlsym(handle, "random")

typealias randomFunc = @convention(c) () -> CInt
let f = unsafeBitCast(sym, randomFunc.self)
let result = f()
dlclose(handle)
print(result)