/*
 * The variable descriptor may be the descriptor of either a file
 * or of a socket.
 */
cc = read(descriptor, buf, nbytes)
int cc, descriptor; char *buf; int nbytes;

/* 
 * An iovec can include several source buffers. 
 */ 
cc = readv(descriptor, iov, iovcnt) 
int cc, descriptor; struct iovec *iov; int iovcnt;

cc = write(descriptor, buf, nbytes) 
int cc, descriptor; char *buf; int nbytes;

cc = writev(descriptor, iovec, ioveclen) 
int cc, descriptor; struct iovec *iovec; int ioveclen;

/* 
 * The variable ``sock'' must be the descriptor of a socket. 
 * Flags may include MSG_OOB and MSG_PEEK. 
 */ 
cc = send(sock, msg, len, flags) 
int cc, sock; char *msg; int len, flags;

cc = sendto(sock, msg, len, flags, to, tolen) 
int cc, sock; char *msg; int len, flags; struct sockaddr *to; int tolen;

cc = sendmsg(sock, msg, flags) 
int cc, sock; struct msghdr msg[]; int flags;

cc = recv(sock, buf, len, flags) 
int cc, sock; char *buf; int len, flags;

cc = recvfrom(sock, buf, len, flags, from, fromlen) 
int cc, sock; char *buf; int len, flags; struct sockaddr *from; int *fromlen;

cc = recvmsg(sock, msg, flags) 
int cc, socket; struct msghdr msg[]; int flags;


Figure 10 -- Varieties of read and write commands