1 .\" Copyright (c) 1980, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 3. All advertising materials mentioning features or use of this software
13 .\" must display the following acknowledgement:
14 .\" This product includes software developed by the University of
15 .\" California, Berkeley and its contributors.
16 .\" 4. Neither the name of the University nor the names of its contributors
17 .\" may be used to endorse or promote products derived from this software
18 .\" without specific prior written permission.
20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 .\" @(#)write.2 8.5 (Berkeley) 4/2/94
33 .\" $FreeBSD: src/lib/libc/sys/write.2,v 1.12.2.8 2002/10/13 17:42:14 schweikh Exp $
34 .\" $DragonFly: src/lib/libc/sys/write.2,v 1.5 2006/04/27 16:01:33 swildner Exp $
52 .Fn write "int d" "const void *buf" "size_t nbytes"
54 .Fn writev "int d" "const struct iovec *iov" "int iovcnt"
56 .Fn pwrite "int d" "const void *buf" "size_t nbytes" "off_t offset"
58 .Fn pwritev "int d" "const struct iovec *iov" "int iovcnt" "off_t offset"
63 of data to the object referenced by the descriptor
65 from the buffer pointed to by
70 perform the same action, but gather the output data
73 buffers specified by the members of the
75 array: iov[0], iov[1], ..., iov[iovcnt\|-\|1].
79 perform the same function, but write to the specified position in
80 the file without modifying the file pointer.
88 structure is defined as:
90 .Bd -literal -offset indent -compact
92 char *iov_base; /* Base address. */
93 size_t iov_len; /* Length. */
99 entry specifies the base address and length of an area
100 in memory from which data should be written.
104 will always write a complete area before proceeding
107 On objects capable of seeking, the
110 given by the pointer associated with
116 the pointer is incremented by the number of bytes which were written.
118 Objects that are not capable of seeking always write from the current
119 position. The value of the pointer associated with such an object
122 If the real user is not the super-user, then
124 clears the set-user-id bit on a file.
125 This prevents penetration of system security
128 a writable set-user-id file
129 owned by the super-user.
131 When using non-blocking I/O on objects such as sockets that are subject
136 may write fewer bytes than requested;
137 the return value must be noted,
138 and the remainder of the operation should be retried when possible.
140 Upon successful completion the number of bytes which were written
141 is returned. Otherwise a -1 is returned and the global variable
143 is set to indicate the error.
150 will fail and the file pointer will remain unchanged if:
154 is not a valid descriptor open for writing.
156 An attempt is made to write to a pipe that is not open
157 for reading by any process.
159 An attempt is made to write to a socket of type
161 that is not connected to a peer socket.
163 An attempt was made to write a file that exceeds the process's
164 file size limit or the maximum file size.
168 or data to be written to the file
169 points outside the process's allocated address space.
171 The pointer associated with
175 There is no free space remaining on the file system
178 The user's quota of disk blocks on the file system
179 containing the file has been exhausted.
181 An I/O error occurred while reading from or writing to the file system.
183 A signal interrupted the write before it could be completed.
185 The file was marked for non-blocking I/O,
186 and no data could be written immediately.
188 An attempt was made to write over a disk label area at the beginning
193 to enable writing on the disk label area.
200 may return one of the following errors:
202 .It Bq Er EDESTADDRREQ
203 The destination is no longer available when writing to a
205 domain datagram socket on which
207 had been used to set a destination address.
210 was less than or equal to 0, or greater than
223 array overflowed a 32-bit integer.
225 The mbuf pool has been completely exhausted when writing to a socket.
232 calls may also return the following errors:
235 The specified file offset is invalid.
237 The file descriptor is associated with a pipe, socket, or FIFO.
248 function call is expected to conform to
254 functions are expected to conform to
259 function call was added in
273 function call appeared in