HELP
An object that reads data from a file using
I/O transactions.

USE
Use From File object to read a wide variety
of file encodings and formats.  From File is
especially useful for importing data files
generated by other software packages.

When several From File objects refer to
the same disc file, a single read pointer is
maintained for all such objects even if they
are in different threads or different
contexts.  This means that data read by one
From File object is not reread by another
From File object using the same file unless a
REWIND operation has been done on the file.
The file is opened and the file pointer is
reset to the beginning of the file (implied
REWIND) when the first From File object for
that file operates after PreRun.  All files
are closed when the model stops.

From File Actions:

* READ - Reads data from a file using the
specified encoding and format.

* EXECUTE - REWIND repositions the file's
read pointer to the beginning of the file
without erasing the contents of the file.
CLOSE closes an open file.

* WAIT - Waits the specified number of
seconds before executing the next
transaction.

From File Encodings:

* TEXT - Reads text ASCII files written by HP
VEE or other software packages.

* BINARY - Reads all data types from a
machine-specific binary format.

* BINBLOCK - Reads all HP VEE data types from
binary files with IEEE 488.2 definite length
block headers.

* CONTAINER - Reads all data types from a
machine-specific text format.

LOCATION
I/O ==> From ==> File

OPEN VIEW PARAMETERS
Open View provides a field for the data file
name, followed by a list of available
transactions.  The data file name can be
added as a control input.

Open View shows the list of file
transactions to be executed.

OBJECT MENU

* Add Trans - Adds a transaction to the end
(bottom) of the list.

* Insert Trans - Inserts a transaction before
(above) the currently highlighted
transaction.

* Cut Trans - Cuts (deletes) the currently
highlighted transaction, but saves it in the
transaction "cut-and-paste" buffer.

* Copy Trans - Copies the currently
highlighted transaction to the transaction
"cut-and-paste" buffer.

* Paste Trans - Pastes a transaction,
previously "cut" or "copied" to the
"cut-and-paste" buffer, in the position
before the currently highlighted transaction.

NOTES
An EOF (End of File) output terminal can be
added with Add Data Output.  EOF is a special
output terminal that propagates with a nil
container when a transaction attempts to read
data past the End of File.  When an End of
File condition is detected and the EOF output
is activated, none of the other data outputs
are activated, even if they contain newly
read data.

If EOF is detected and there is no EOF
output pin, an error is returned.

To read all of the data in the file, use a
READ ...  ARRAY TO END:  transaction.

SHORT CUTS
To quickly insert a transaction, place the
cursor on a transaction.  Press [CTRL-O] to
insert a transaction over the transaction
where you placed the cursor.

To quickly delete ("kill") a transaction,
place the cursor on that transaction and
press [CTRL-K].

To paste a transaction from the "kill"
buffer press [CTRL-Y].

To quickly move to the next or previous
transaction, press [CTRL-N] or [CTRL-P]
respectively.

SEE ALSO
To File and To/From Named Pipe.

"Using Transaction I/O" in Using HP VEE,
chapter 12.
