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28 .\" @(#)write.2 8.5 (Berkeley) 4/2/94
47 .Fn write "int d" "const void *buf" "size_t nbytes"
49 .Fn pwrite "int d" "const void *buf" "size_t nbytes" "off_t offset"
51 .Fn writev "int d" "const struct iovec *iov" "int iovcnt"
53 .Fn pwritev "int d" "const struct iovec *iov" "int iovcnt" "off_t offset"
60 of data to the object referenced by the descriptor
62 from the buffer pointed to by
67 performs the same action, but gathers the output data
70 buffers specified by the members of the
72 array: iov[0], iov[1], ..., iov[iovcnt\|-\|1].
78 perform the same functions, but write to the specified position in
79 the file without modifying the file pointer.
87 structure is defined as:
89 .Bd -literal -offset indent -compact
91 void *iov_base; /* Base address. */
92 size_t iov_len; /* Length. */
98 entry specifies the base address and length of an area
99 in memory from which data should be written.
103 will always write a complete area before proceeding
106 On objects capable of seeking, the
109 given by the pointer associated with
115 the pointer is incremented by the number of bytes which were written.
117 Objects that are not capable of seeking always write from the current
119 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
142 Otherwise a -1 is returned and the global variable
144 is set to indicate the error.
153 will fail and the file pointer will remain unchanged if:
159 is not a valid descriptor open for writing.
161 An attempt is made to write to a pipe that is not open
162 for reading by any process.
164 An attempt is made to write to a socket of type
166 that is not connected to a peer socket.
168 An attempt was made to write a file that exceeds the process's
169 file size limit or the maximum file size.
173 or data to be written to the file
174 points outside the process's allocated address space.
176 The pointer associated with
180 There is no free space remaining on the file system
183 The user's quota of disk blocks on the file system
184 containing the file has been exhausted.
186 An I/O error occurred while reading from or writing to the file system.
188 A signal interrupted the write before it could be completed.
190 The file was marked for non-blocking I/O,
191 and no data could be written immediately.
193 An attempt was made to write over a disk label area at the beginning
198 to enable writing on the disk label area.
210 may return one of the following errors:
212 .It Bq Er EDESTADDRREQ
213 The destination is no longer available when writing to a
215 domain datagram socket on which
217 had been used to set a destination address.
222 was less than or equal to 0, or greater than
235 array overflowed a 32-bit integer.
237 The mbuf pool has been completely exhausted when writing to a socket.
244 system calls may also return the following errors:
251 The file descriptor is associated with a pipe, socket, or FIFO.
262 system call is expected to conform to
268 system calls are expected to conform to
273 system call appeared in
281 system call appeared in