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Annotation of 43BSDTahoe/man/man2/send.2, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1983 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)send.2      6.4 (Berkeley) 7/21/87
                      6: .\"
                      7: .TH SEND 2 "July 21, 1987"
                      8: .UC 5
                      9: .SH NAME
                     10: send, sendto, sendmsg \- send a message from a socket
                     11: .SH SYNOPSIS
                     12: .nf
                     13: .ft B
                     14: #include <sys/types.h>
                     15: #include <sys/socket.h>
                     16: .PP
                     17: .ft B
                     18: cc = send(s, msg, len, flags)
                     19: int cc, s;
                     20: char *msg;
                     21: int len, flags;
                     22: .PP
                     23: .ft B
                     24: cc = sendto(s, msg, len, flags, to, tolen)
                     25: int cc, s;
                     26: char *msg;
                     27: int len, flags;
                     28: struct sockaddr *to;
                     29: int tolen;
                     30: .PP
                     31: .ft B
                     32: cc = sendmsg(s, msg, flags)
                     33: int cc, s;
                     34: struct msghdr *msg;
                     35: int flags;
                     36: .fi
                     37: .SH DESCRIPTION
                     38: .IR Send ,
                     39: .IR sendto ,
                     40: and
                     41: .I sendmsg
                     42: are used to transmit a message to another socket.
                     43: .I Send
                     44: may be used only when the socket is in a 
                     45: .I connected
                     46: state, while 
                     47: .I sendto
                     48: and
                     49: .I sendmsg
                     50: may be used at any time.
                     51: .PP
                     52: The address of the target is given by
                     53: .I to
                     54: with 
                     55: .I tolen
                     56: specifying its size.
                     57: The length of the message is given by
                     58: .IR len .
                     59: If the message is too long to pass atomically through the
                     60: underlying protocol, then the error EMSGSIZE is returned, and
                     61: the message is not transmitted.
                     62: .PP
                     63: No indication of failure to deliver is implicit in a
                     64: .IR send .
                     65: Return values of \-1 indicate some locally detected errors.
                     66: .PP
                     67: If no messages space is available at the socket to hold
                     68: the message to be transmitted, then
                     69: .I send
                     70: normally blocks, unless the socket has been placed in
                     71: non-blocking I/O mode.
                     72: The
                     73: .IR select (2)
                     74: call may be used to determine when it is possible to
                     75: send more data.
                     76: .PP
                     77: The
                     78: .I flags
                     79: parameter may include one or more of the following:
                     80: .PP
                     81: .nf
                     82: .RS
                     83: .ta \w'#define\ \ 'u +\w'MSG_DONTROUTE\ \ \ 'u +\w'0x\0\0\0\ \ 'u
                     84: #define        MSG_OOB 0x1     /* process out-of-band data */
                     85: #define        MSG_DONTROUTE   0x4     /* bypass routing, use direct interface */
                     86: .RE
                     87: .fi
                     88: The flag MSG_OOB is used to send \*(lqout-of-band\*(rq
                     89: data on sockets that support this notion (e.g. SOCK_STREAM);
                     90: the underlying protocol must also support \*(lqout-of-band\*(rq data.
                     91: MSG_DONTROUTE is usually used only by diagnostic or routing programs.
                     92: .PP
                     93: See 
                     94: .IR recv (2)
                     95: for a description of the
                     96: .I msghdr
                     97: structure.
                     98: .SH "RETURN VALUE
                     99: The call returns the number of characters sent, or \-1
                    100: if an error occurred.
                    101: .SH "ERRORS
                    102: .TP 20
                    103: [EBADF]
                    104: An invalid descriptor was specified.
                    105: .TP 20
                    106: [ENOTSOCK]
                    107: The argument \fIs\fP is not a socket.
                    108: .TP 20
                    109: [EFAULT]
                    110: An invalid user space address was specified for a parameter.
                    111: .TP 20
                    112: [EMSGSIZE]
                    113: The socket requires that message be sent atomically,
                    114: and the size of the message to be sent made this impossible.
                    115: .TP 20
                    116: [EWOULDBLOCK]
                    117: The socket is marked non-blocking and the requested operation
                    118: would block.
                    119: .TP 20
                    120: [ENOBUFS]
                    121: The system was unable to allocate an internal buffer.
                    122: The operation may succeed when buffers become available.
                    123: .TP 20
                    124: [ENOBUFS]
                    125: The output queue for a network interface was full.
                    126: This generally indicates that the interface has stopped sending,
                    127: but may be caused by transient congestion.
                    128: .SH SEE ALSO
                    129: fcntl(2), recv(2), select(2), getsockopt(2), socket(2), write(2)

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