Skip to content
⎕FSTIE FSTIE

File Share Tie {R}←X ⎕FSTIE Y

Y must be 0 or a simple 1 or 2 element integer vector containing an available file tie number to be associated with the file for further file operations, and an optional passnumber.  If the passnumber is omitted it is assumed to be zero.  The tie number must not already be associated with a tied file.

X must be a simple character scalar or vector which specifies the name of the file to be tied.  The file must be named in accordance with the operating system's conventions, and may be specified with a relative or absolute pathname. If no file extension is supplied, the set of extensions specified by the  CFEXT parameter are tried one after another until the file is found or the set of extensions is exhausted. See  CFEXT.

The file must exist and be accessible by the user.  If it is already tied by another task, it must not be tied exclusively.

The shy result of ⎕FSTIE is the tie number of the file.

Automatic Tie Number Allocation

A tie number of 0 as argument to a create, share tie or exclusive tie operation, allocates the first (closest to zero) available tie number and returns it as an explicit result. This allows you to simplify code. For example:

from: 

      tie←1+⌈/0,⎕FNUMS  ⍝ With next available number,
      file ⎕FSTIE tie   ⍝ ... share tie file.

to: 

      tie←file ⎕FSTIE 0 ⍝ Tie with 1st available number.

Example

      'SALES' ⎕FSTIE 1
 
      '../budget/COSTS' ⎕FSTIE 2

Variant Options

Mode

Writing to a component file is not always permitted. For example, restrictions on writing to a component file might be imposed by operating system permissions, the host filesystem, or individual component file property settings.

The Mode variant option specifies whether the file that is being tied will only be read or must be writeable. Possible values are:

  • P (tied as permitted) – the file will be tied for write access if possible, otherwise for read access only. If the file permissions do not allow the file to be written to, any subsequent attempt to write to it will fail. This is the default.
  • R (read mode) – the file will be tied for read access only; any subsequent attempt to write to it will fail.
  • W (write mode) – if the file permissions do not allow the file to be written to, the attempt to tie it will fail.

The Mode variant option is independent of any file access controls managed using an access matrix.

Example

      'cf' (⎕FSTIE⍠'Mode' 'W') 1
FILE ACCESS ERROR: cf.dcf: File is not writable
      'cf'(⎕FSTIE⍠'Mode' 'W')1
                ∧

Information

Small-span (32-bit) component files are currently read-only; this support is scheduled for removal in a future release, after which it will not be possible to tie small-span component files. Dyalog Ltd recommends using ⎕FCOPY to convert any such files to large-span (64-bit). For information on how to identify calls to small-span component files in your existing codebase, see the Release Notes.