#536 OPENAPPEND doesn't immediately set WRITEPOS to end of file

[David Costanzo]

OPENAPPEND is documented to set the file position to the end of the file so that all writes are appended to the file. However, after calling OPENAPPEND, WRITEPOS outputs 0, instead of the position of the end of the file. FMSLogo seems to delay setting the WRITEPOS to the end until the first time the file is written to.

This bug prevents, for example, a programmer from determining if the file is empty after calling OPENAPPEND.

I have reproduced this bug in UCBLogo 6.0 and FMSLogo 6.10.0. It's likely that this bug was inherited from UCBLogo into MSWLogo into FMSLogo.

How Reproducible
Every time

Steps to Reproduce
Run the following proceedure

TO RUNTEST
  ; Create a file with a line of text.
  OPENWRITE "testfile.txt
  SETWRITE  "testfile.txt
  PRINT "Hello
  SETWRITE []
  CLOSE "testfile.txt

  ; Open for appending
  OPENAPPEND "testfile.txt
  SETWRITE   "testfile.txt

  ; Show initial write position
  MAKE "writepos WRITEPOS
  SETWRITE []
  SHOW :WRITEPOS

  CLOSE "testfile.txt
END

What Happens
The SHOW :WRITEPOS prints 0.

Expected Result
The SHOW :WRITEPOS prints 7 (Hello = 5 + end-of-line=2 ).

[David Costanzo]

Fixed by [r5161]. The fix will be included in FMSLogo 7.7.0.