.help bfwrit Sep86 imfort.bfio
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NAME
bfwrit -- write to a binary file at the specified offset
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SYNOPSIS
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integer function bfwrit (fd, buf, nchars, offset)

integer		fd		#I BFIO file descriptor of open file
typeless	buf(*)		#I buffer containing file data
integer		nchars		#I number of SPP chars to be written
integer		offset		#I 1-indexed char offset into file

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DESCRIPTION
The \fIbfwrit\fR procedure writes \fInchars\fR char units of storage from
the user supplied buffer to the file opened on file descriptor \fIfd\fR
starting at the one-indexed char file offset \fIoffset\fR.  Any number of
chars may be written starting at any char file offset.
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RETURN VALUE
The actual number of char units of storage written is returned as the function
value; it is probably an error if this is not equal to \fInchars\fR.
A negative function value indicates that the write failed for some reason,
e.g., the file descriptor was invalid, the file offset was out of range,
or an actual physical write error occurred.
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NOTES
The entire contents of the internal BFIO file buffer are always written,
even when writing at the end of file, hence it is not possible to write
odd-sized files with the BFIO interface (partial blocks can however be
read with \fIbfread\fR).
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SEE ALSO
bfread
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