98 lines
2.4 KiB
Groff
98 lines
2.4 KiB
Groff
.\" Copyright (c) 1980 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)write.2 6.5 (Berkeley) 5/14/86
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.\"
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.TH WRITE 2 "May 14, 1986"
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.UC 4
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.SH NAME
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write \- write output
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.SH SYNOPSIS
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.nf
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.ft B
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#include <sys/types.h>
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#include <unistd.h>
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ssize_t write(int \fId\fP, const void *\fIbuf\fP, size_t \fInbytes\fP)
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.fi
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.SH DESCRIPTION
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.B Write
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attempts to write
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.I nbytes
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of data to the object referenced by the descriptor
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.I d
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from the buffer pointed to by
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.IR buf .
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.PP
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On objects capable of seeking, the \fBwrite\fP starts at a position
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given by the pointer associated with
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.IR d ,
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see
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.BR lseek (2).
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Upon return from
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.BR write ,
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the pointer is incremented by the number of bytes actually written.
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.PP
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Objects that are not capable of seeking always write from the current
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position. The value of the pointer associated with such an object
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is undefined.
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.PP
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When using non-blocking I/O on objects such as TCP/IP channels that are
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subject to flow control,
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.B write
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may write fewer bytes than requested;
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the return value must be noted,
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and the remainder of the operation should be retried when possible.
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.SH "RETURN VALUE
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Upon successful completion the number of bytes actually written
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is returned. Otherwise a \-1 is returned and the global variable
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.B errno
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is set to indicate the error.
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.SH ERRORS
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.B Write
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will fail and the file pointer will remain unchanged if one or more
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of the following are true:
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.TP 15
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[EBADF]
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\fID\fP is not a valid descriptor open for writing.
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.TP 15
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[EPIPE]
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An attempt is made to write to a pipe that is not open
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for reading by any process.
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.TP 15
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[EPIPE]
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An attempt is made to write to a TCP channel
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that is not connected to a peer socket.
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.TP 15
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[EFBIG]
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An attempt was made to write a file that exceeds the process's
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file size limit or the maximum file size.
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.TP 15
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[EFAULT]
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Part of the data to be written to the file
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points outside the process's allocated address space.
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.TP 15
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[ENOSPC]
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There is no free space remaining on the file system
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containing the file.
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.ig
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.TP 15
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[EDQUOT]
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The user's quota of disk blocks on the file system
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containing the file has been exhausted.
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..
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.TP 15
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[EIO]
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An I/O error occurred while reading from or writing to the file system.
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.TP 15
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[EAGAIN]
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The file was marked for non-blocking I/O,
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and no data could be written immediately.
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.SH "SEE ALSO"
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.BR fcntl (2),
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.BR lseek (2),
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.BR open (2),
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.BR pipe (2),
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.BR read (2).
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