.help zalocd Aug85 "System Interface"
.ih
NAME
zalocd -- set, remove, or query device allocation
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SYNOPSIS
.nf
zalocd (device, action, status)

packed	char device[ARB]	# device 1
int	action			# operation to be performed
int	status
.fi
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DESCRIPTION
The named logical device is either allocated or deallocated, or the device
allocation status is queried, depending upon the value of the \fIaction\fR
argument.

.nf
	DEALLOCATE_DEVICE	0
	ALLOCATE_DEVICE		1
	QUERY_ALLOCATION	2
.fi

By allocating a device we mean that [1] the device is reserved for use by the
owner of the process issuing the request, and [2] the device is readied for
opening by the process issuing the request, or by a subprocess of the process
issuing the request.  If the device is a tape drive the drive should be
mounted foreign (unlabeled) and the density should be set if so indicated
in the 

It is not an error to attempt to allocate a device which is already allocated,
nor is it an error to attempt to deallocate a device which is not currently
allocated.
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RETURN VALUE
OK is returned if a set_protection or remove_protection operation is
successful.  YES (protected) or NO (not protected) is returned in response
to a query.  ERR is returned if the named file does not exist or if
the operation cannot be performed.
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NOTES
FIO will query for file protection before attempting to delete a file.
If the host system does not provide file protection facilities they can
often be faked by creating a hidden file in the same directory; the existence
of the file will indicate that the file is protected.  If the hidden file
technique is used, the hidden file should not be seen when the directory
is read by the high level code.
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SEE ALSO
zfdele
.endhelp