🔗Sockets (net/common)

net/common.nim is the platform-agnostic socket layer underneath TCP and UDP. It is auto-initialized at module load (initNet()), and on POSIX it re-exports std/posix, so the raw socket/bind/connect/send/recv/accept/… syscalls are also in scope.

🔗Address resolution

let addrBuf = resolveAddr("example.com", 443)              # first result
let all     = resolveAddrAll("example.com", 443)           # all results
let ip      = sockaddrFromIp("127.0.0.1", 9000)            # literal only
isIpAddress("10.0.0.1")                                    # true

resolveAddr* uses the platform resolver (getaddrinfo) and is the blocking path used at startup (e.g. tcp.listen). For run-time resolution on the loop, use async DNS.

🔗Socket options

setNonBlocking(fd)
setReuseAddr(fd)
setReusePort(fd)
setTcpNoDelay(fd)
setTcpCork(fd, enable = true)
setIpv6Only(fd)

🔗Raw I/O wrappers

sockSend(fd, addr buf, buf.len)
sockRecv(fd, addr buf, buf.len)
sockWritev(fd, iov, iovcnt)
sockClose(fd)
sockShutdown(fd, how)
lastSocketError()
sockWouldBlock()       # errno == EAGAIN/EWOULDBLOCK
sockInterrupted()      # errno == EINTR
sockInProgress()       # errno == EINPROGRESS
getSockLen(addr sockaddr)      # length of the sockaddr structure

🔗Zero-copy file transmission

sendfile moves file bytes to a socket without bouncing them through userspace:

var off: int64 = 0
var remain: int64 = fileSize
while remain > 0:
  let n = sendFileChunk(sockFd, fileFd, off, remain)   # 0 = EOF, -1 = error
  if n <= 0: break
  remain -= n

SendFileChunkSize is 65536; DefaultSendFileChunk is 0 (send all). On Windows powpow uses TransmitFile instead.

🔗File helpers

let fd = openFileRead("/path/to/file")
let size = getFileSize(fd)
readFile(fd, buf, bufLen)      # int64 bytes read
seekFile(fd, offset)
closeFile(fd)

🔗Errors

All socket/network errors surface as NetError* = object of CatchableError.

🔗Unix domain sockets

listenUnix / connectUnix (TCP and HTTP) are POSIX-only. UNIX_PATH_MAXis 107.

🔗API reference

Full signatures: common API. Also see TCP and UDP.