amos-pro-bsdsocket-extension/API.md

BSD Socket Extension API

Most functions will return -2 if the bsdsocket.library is not open.

Setup

ADDR=Socket Library Open

Try to open bsdsocket.library version 4.

Returns

• 0 if opening failed
• Memory address of library on success
  • If needed, you'll be able to directly access library functions using this address.

Socket Library Close

Close bsdsocket.library. This is safe to call if the library is not open

RESULT=Socket Set Nonblocking(Socket, IsNonblocking BOOL)

Make a socket blocking (False, default), or nonblocking (True).

Returns

• Result of IoctlSocket call.

RESULT=Socket Reuse Addr(Socket)

Make a listening socket reuse the address it's trying to bind to. You probably want to call this right before Socket Listen.

Returns

• Result of setsockopt call.

Connections

SOCKET=Socket Create Inet Socket

Create a new Internet socket for reading or writing.

Returns

• Socket number on success
• -1 on failure

RESULT=Socket Connect(Socket to IPAddress$, Port)

Attempt to connect to a remote host. Currently doesn't support DNS lookups.

Returns

• 0 on connected
• -1 on error
  • If your socket is non-blocking, you have to check the socket with Socket Select and Socket Getsockopt Int to see if the connection succeeded
• -11 port out of range

RESULT=Socket Reuse Addr(Socket)

Set a server socket to reuse an interface and port that had been used recently. You likely want this if you're building something that listens on a port for connections. This calls setsockopt() for you.

Returns

The result of calling setsockopt() while setting your socket to reuse addresses.

RESULT=Socket Bind(Socket to IPAddress, Port)

Attempt to bind a socket to a network interface. Use the string "IPADDR_ANY" for IPAddress to bind to all interfaces.

Returns

• 0 on success
• -1 on other error
• -11 port out of range

RESULT=Socket Listen(Socket)

Start listening for connections.

Returns

• 0 on success
• -1 on failure

NEW_SOCKET=Socket Accept(Socket)

Get the socket that connected to this one. Wait for a connect if this socket is blocking.

Warning

If this socket is blocking (the default), you will likely get AMOS stuck in a state you can't recover from, due to how AMOS takes over system signals! Be sure to make your socket non-blocking and use Fdsets and Select!

Returns

• The remote socket number on success
• -1 on failure

RESULT=Socket Async Wait Reading(Socket, Wait_ms)

Wait the given number of milliseconds for the nonblocking socket to be ready for reading. Use this when you're waiting for a client to connect to you, or if you're waiting for a remote socket to send you data.

Returns

• 0 on timeout.
• -1 on error. Use Socket Errno for more detail.
• 1 on success.

RESULT=Socket Async Wait Writing(Socket, Wait_ms)

Wait the given number of milliseconds for the nonblocking socket to be ready for writing. Use this when you're connecting to a remote server and want to know if the connection has been completed.

Returns

• 0 on timeout.
• -1 on error. Use Socket Errno for more detail.
• -3 on the socket having an error.
  • If you're using this function to test for a successful connection and receive a -3, close and reopen the socket, otherwise subsequent checks will return 1.
• 1 on success.

RESULT=Socket Set Timeout(Socket, Wait_ms)

Set a socket to timeout after Wait_ms milliseconds if reading or writing doesn't complete.

Returns

• 0 on success
• -1 on error

RESULT=Socket Close(Socket)

Close a socket.

Returns

• 0 on success
• -1 on error

Data Transfers

SENT=Socket Send$(Socket, String$)

Send a string to a connected socket.

Bugs

For some reason, this command performs incorrectly when used in a Procedure to send a passed-in variable, and Varptr() is not called on the string variable to be sent beforehand within the procedure itself. I believe this is a bug in AMOS itself. You'll know you're having this issue if the byte count returned is abnormally high.

If you're using this in a Procedure, call Varptr() first:

Procedure SEND_STRING[SOCKET, S$]
  ' _shrug_
  _=Varptr(S$)

  BYTES=Socket Send$(SOCKET,S$)
End Proc

Returns

• Number of characters sent
• -1 on other error

SENT=Socket Send(Socket, Data Pointer, Length)

Send a block of data to a connected socket.

Returns

• Number of characters sent
• -1 on other error

DATA$=Socket Recv$(Socket, MaxLength)

Retrieve at most MaxLength bytes from Socket, and put them into a string. If Len(DATA$) < MaxLength, you've read the last bit of data from the socket.

Returns

• String of data, which is blank if there is no more data.

LENGTH=Socket Recv(Socket to Dataptr, MaxLength)

Retrieve at most MaxLength bytes from Socket, and put them into the memory address at Dataptr.

Returns

• Count of bytes read
• -1 on error

Informational

HOST=Socket Get Host(Socket)

Get the IPv4 (Long) host value the given socket is using.

Returns

• Host as a long value

PORT=Socket Get Port(Socket)

Get the 16-bit port (Word) value the given socket is using.

Returns

• Port as a word value

RESULT$=Socket Inet Ntoa$(Host)

Turn a long Host address into a string.

Returns

• IP address as string

RESULT=Socket Errno

Get the error from the last command. Note that this is not cleared on a successful command!

Returns

Error number from last call. Look in <sys/error.h> for more details.

RESULT$=Dns Get Address By Name$(Domain Name$)

Look up the first IP address associated with this hostname.

Warning

This is dependent on your stack's name resolution. If DNS lookups aren't working correctly, you may have to wait for the lookup to time out. There's no way to set this timeout, or cancel or override it via AMOS.

Returns

String with IP address, or blank string on error.

RESULT=Socket Status(Socket)

Returns basic connection information about a socket.

Warning

Since none of the socket processing of this extension happens in the background, you're likely better off using other means to detect socket status.

• Disconnected: Try a recv and get zero bytes back. Check Socket Errno.
• Broken: Try a send. If it fails, check Socket Errno.
• Ready: Use the Async Wait functions.

Returns

Status of socket:

• 0 = Closed
• 2 = Listening
• 6 = Connecting
• 7 = Connected

Low Level

RESULT=Socket Setsockopt Int(Socket, Option, Value)

Set a socket option. You probably want SO_REUSEADDR, which is Option=$4, and you want Value=True. Or, use Socket Reuse Addr().

Returns

• Result of setsockopt call

RESULT=Socket Getsockopt Int(Socket, Option)

Get a socket option. You probably want SO_ERROR, which is Option=$1007, and it's what you check when you attempt a connection with a non-blocking socket.

Returns

• Result of getsockopt call

ADDR=Socket Fdset Zero(fd_set)

Clear out the specified fd_set.

Returns

• Address to that particular fd_set
• -1 if fd_set out of range. You get 16 of them.

ADDR=Socket Fdset Set(fd_set, Socket to Value BOOL)

Set or clear a socket bit in an fd_set.

Returns

• Address to that particular fd_set
• -1 if fd_set is out of range or socket is out of range.

RESULT=Socket Fdset Is Set(fd_set, Socket)

See if the particular socket remained after a Socket Select call.

Returns

• True or False if the socket is set or not

RESULT=Socket Select(Max Socket, Read fd_set, Write fd_set, Error fd_set, TimeoutMS)

Wait for the specified number of milliseconds. If any of the sockets in any of the fd_sets become interesting during that time, stop waiting, clear out the uninteresting sockets in the fd_sets, and return how many sockets were left.

Returns

• 0 on timeout
• -1 on error

• of interesting sockets on success