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    Length: 1332 (0x534)
    Types: TextFile
    Notes: UNIX file
    Names: »write.2«

└─⟦26887b7e0⟧ Bits:30009717 Comet 32 harddisk image
    └─⟦28c352965⟧ »/a« UNIX Filesystem
        └─⟦this⟧ »usr/man/man2/write.2« 

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	@(#)write.2	2.1	7/1/84
	@(#)Copyright (C) 1983 by National Semiconductor Corp.
..
.TH WRITE 2 
.UC 4
.SH NAME
write \- write on a file
.SH SYNOPSIS
.nf
.B write(fildes, buffer, nbytes)
.B char *buffer;
.fi
.SH DESCRIPTION
.I Fildes
is a word returned from a
successful
.I open,
.I creat,
.I dup,
or
.IR pipe (2)
call.
.PP
.I Buffer
is the address of
.I nbytes
contiguous
bytes which are written on the output file.
The number of characters actually written is returned.
It should be regarded as an error
if this is not the same as requested.
.PP
Writes which are multiples
of 1024 characters long and begin on a 1024-byte boundary
in the file
are more efficient than any others.
.PP
.IR Write s
to the control terminal by a process
which is not in the process group of the terminal
and which is not ignoring or holding SIGTTOU signals
cause the writer's process group
to receive a SIGTTOU signal
(See
.IR jobs (3)
and the description of the LTOSTOP option in
.IR tty (4)
for details).
.PP
On some systems
.I write
clears the set-user-id bit on a file.
This prevents penetration of system security
by a user who
\*(lqcaptures\*(rq a writeable set-user-id file
owned by the super-user.
.SH "SEE ALSO"
creat(2), open(2), pipe(2)
.SH DIAGNOSTICS
Returns
\-1 on error: bad descriptor, buffer address, or
count; physical I/O errors.