amiga-bootcamp/12_networking/bsdsocket.md

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bsdsocket.library — BSD Socket API Reference

Overview

bsdsocket.library is the AmigaOS implementation of the BSD socket API. It is provided by the active TCP/IP stack (AmiTCP, Miami, Roadshow). See TCP/IP Stacks for how the stack architecture works and how it differs from Unix. See Protocols for working code examples.

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Per-Task Library Base

Unlike Unix (kernel-managed fd table), each Amiga task must open its own private SocketBase:

struct Library *SocketBase = OpenLibrary("bsdsocket.library", 4);
if (!SocketBase)
{
    Printf("No TCP/IP stack running\n");
    return;
}

/* Configure per-task error variable: */
LONG errno;
SocketBaseTags(
    SBTM_SETVAL(SBTC_ERRNOPTR(sizeof(LONG))), (ULONG)&errno,
    SBTM_SETVAL(SBTC_LOGTAGPTR),              (ULONG)"myapp",
    TAG_DONE);

Caution

Never share SocketBase between tasks. Each task MUST OpenLibrary its own copy. Sharing causes socket state corruption and random crashes. This is the #1 Amiga networking bug.

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Function Table (LVO Mapping)

LVO	Function	BSD Equivalent
−30	socket(domain, type, protocol)	socket()
−36	bind(sock, name, namelen)	bind()
−42	listen(sock, backlog)	listen()
−48	accept(sock, addr, addrlen)	accept()
−54	connect(sock, name, namelen)	connect()
−60	sendto(sock, buf, len, flags, to, tolen)	sendto()
−66	send(sock, buf, len, flags)	send()
−72	recvfrom(sock, buf, len, flags, from, fromlen)	recvfrom()
−78	recv(sock, buf, len, flags)	recv()
−84	shutdown(sock, how)	shutdown()
−90	setsockopt(...)	setsockopt()
−96	getsockopt(...)	getsockopt()
−102	gethostbyname(name)	gethostbyname()
−108	gethostbyaddr(addr, len, type)	gethostbyaddr()
−114	getnetbyname(name)	getnetbyname()
−168	Errno()	errno
−174	CloseSocket(sock)	close()
−180	WaitSelect(nfds, rd, wr, ex, timeout, sigmask)	select() + signals
−210	inet_addr(cp)	inet_addr()
−216	Inet_NtoA(in)	inet_ntoa()
−222	inet_makeaddr(net, host)	inet_makeaddr()
−252	getservbyname(name, proto)	getservbyname()
−270	SocketBaseTagList(tags)	(Amiga-specific)

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WaitSelect — Amiga-Enhanced select()

The key Amiga-specific extension: WaitSelect simultaneously waits on socket file descriptors and Exec signal bits. This replaces the need for separate threads — a single event loop can handle sockets, windows, timers, and ARexx:

LONG WaitSelect(LONG nfds,
                fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
                struct timeval *timeout,
                ULONG *sigmask);
/* sigmask: on entry = signals to also wait for
            on exit  = which signals fired */

See protocols.md for a complete working example combining socket I/O with Intuition window events.

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Error Handling

/* Amiga sockets use Errno() instead of global errno: */
LONG sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock < 0)
{
    LONG err = Errno();
    Printf("socket() failed: error %ld\n", err);
}

/* Or set up a per-task errno pointer (recommended): */
LONG myErrno;
SocketBaseTags(
    SBTM_SETVAL(SBTC_ERRNOPTR(sizeof(LONG))), (ULONG)&myErrno,
    TAG_DONE);
/* Now myErrno is updated automatically after each call */

Common Error Codes

Value	Name	Meaning
48	EADDRINUSE	Address already in use
60	ETIMEDOUT	Connection timed out
61	ECONNREFUSED	Connection refused
64	EHOSTDOWN	Host is down
65	EHOSTUNREACH	No route to host

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Differences from BSD/POSIX Sockets

Aspect	BSD/POSIX	Amiga bsdsocket.library
Close socket	close(fd)	CloseSocket(sock) — close() is AmigaDOS
Error variable	Global errno	Call Errno() or set SBTC_ERRNOPTR
Multiplexing	select() / poll() / epoll()	WaitSelect() — also waits on Exec signals
Headers	<sys/socket.h>	<proto/socket.h> or stack-specific
Lifecycle	Kernel-managed	Must OpenLibrary/CloseLibrary per task
fd namespace	Shared with files	Sockets are separate from DOS file handles
Multi-thread	fd shared across threads	SocketBase is per-task, not shareable

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References

• Roadshow SDK documentation
• AmiTCP SDK: bsdsocket.h and autodocs
• See also: tcp_ip_stacks.md — stack architecture and configuration
• See also: protocols.md — working code examples (TCP, UDP, DNS)
• See also: sana2.md — network device driver layer below the stack