Deprecated OSError, and modified it to require an explicit OS error code.

The deprecated functions include the OSError and OSErrorMsg, the name did not change however the signature of the new functions did. They now require a TOSErrorCode value be passed to them. This value can be retrieved using OSLastError. The reason this was done is because on Windows any win api call can reset the last error code to 0, this change allows the user to immediately grab the error code and worry about the string representation later if needs be.

lib/pure/asyncio.nim

@@ -167,7 +167,7 @@ proc AsyncSocket*(domain: TDomain = AF_INET, typ: TType = SOCK_STREAM,
   result = newAsyncSocket()
   result.socket = socket(domain, typ, protocol, buffered)
   result.proto = protocol
-  if result.socket == InvalidSocket: OSError()
+  if result.socket == InvalidSocket: OSError(OSLastError())
   result.socket.setBlocking(false)
 
 proc toAsyncSocket*(sock: TSocket, state: TInfo = SockConnected): PAsyncSocket =
@@ -349,7 +349,7 @@ proc acceptAddr*(server: PAsyncSocket, client: var PAsyncSocket,
     client.sslNeedAccept = false
     client.info = SockConnected
 
-  if c == InvalidSocket: OSError()
+  if c == InvalidSocket: SocketError(server.socket)
   c.setBlocking(false) # TODO: Needs to be tested.
   
   # deleg.open is set in ``toDelegate``.
@@ -642,8 +642,7 @@ when isMainModule:
   proc testRead(s: PAsyncSocket, no: int) =
     echo("Reading! " & $no)
     var data = ""
-    if not s.readLine(data):
-      OSError()
+    if not s.readLine(data): return
     if data == "":
       echo("Closing connection. " & $no)
       s.close()