EOF Function

Tests the specified file unit for the end-of-file condition.

Usage

result = EOF(unit)

Input Parameters

unit

The logical unit number (LUN) of the file to be tested.

Returned Value

Returns 1 if the file is positioned at the end of the file. Otherwise, returns 0.

Keywords

Discussion

OpenVMS Users: Under OpenVMS, the EOF function has the following limitations:

It does not work with files accessed via DECNET.
It is meaningless when used with files having an indexed organization structure.

In such cases, we recommend using the ON_IOERROR procedure to handle end-of-file.

Example

In this example, a file of test data is created. That file is then read and printed until the end-of-file condition is detected by EOF.

OPENW, unit, 'eoffile.dat', /Get_Lun

; Open the file eoffile.dat for writing.

PRINTF, unit, 'This is'
PRINTF, unit, 'some sample'
PRINTF, unit, 'data.'

; Write some text to the file.

FREE_LUN, unit

; Close the file and free the associated unit number.

OPENR, unit, 'eoffile.dat', /Get_Lun

; Open the file eoffile.dat for reading.

a = ' '

; Define a string variable.

WHILE NOT eof(unit) DO BEGIN &$

 READF, unit, a &$
 PRINT, a &$

; Read data and print it until end-of-file.

ENDWHILE
This is
some sample
data.
FREE_LUN, unit

See Also

For information on opening files and choosing LUNs, see Opening and Closing Files of the PV-WAVE Programmer's Guide.

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