On 09/24/2017 10:23 PM, ToddAndMargo wrote:
On 09/23/2017 12:34 PM, Brandon Allbery wrote:
On Sat, Sep 23, 2017 at 2:34 AM, ToddAndMargo <toddandma...@zoho.com <mailto:toddandma...@zoho.com>> wrote:


    I see ":truncate".  This seems liek it will do the trick.
    Problem: I would like to read from the file first before
    truncating (ro).

    Is there a way to do this, or should I
        1) open the handle with :ro
        2) read what I want from it
        3) close the handle
        4) reopen the handle with :w and overwrite what I want?


You have to do it the long way. I don't think we expose a binding to ftruncate() that would let you open it r/.w, red from it, truncate, and write.

That said, there's actually a good reason for that: is it okay to trash the file if something goes wrong? You might prefer to *rename* the old file instead of overwriting, so you can recover if necessary.

That is what I did.  Thank you for the confirmation!

I suppose I should say at this point that the purpose of the file
is to be a single line with the date the program was last run
in it.  If the current date's month and the month in the file
differ, it triggers an event in my program.

--
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Computers are like air conditioners.
They malfunction when you open windows
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