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Re^2: How do I tell if a handle is open for writing?

by DrWhy (Chaplain)
on Nov 07, 2005 at 17:16 UTC ( #506448=note: print w/ replies, xml ) Need Help??


in reply to Re: How do I tell if a handle is open for writing?
in thread How do I tell if a handle is open for writing?

Correct me if I'm wrong here, but doesn't -w myfilehandle tell you whether the file that myfilehandle is pointing to has its writable bits set? That's not what I want to know. I want to know if the filehandle is open for writing. You could open a writable file for reading. Then you couldn't write to it with that handle even though passing that handle to -w would still return true. Or have I been smoking the curtains again?

--DrWhy

"If God had meant for us to think for ourselves he would have given us brains. Oh, wait..."


Comment on Re^2: How do I tell if a handle is open for writing?
Re^3: How do I tell if a handle is open for writing?
by Zaxo (Archbishop) on Nov 07, 2005 at 19:06 UTC
    Or have I been smoking the curtains again?

    No, the curtains are safe. I've added to my reply a sub that Does What You Want.

    After Compline,
    Zaxo

      Ah. That looks much more to the point :) I like this fcntl()-based solution better than sgifford's solution (print nothing) because it more directly answers the question at hand. Which is not to say that sgifford's solution is bad; it has the advantage that it will catch some writability problems not related to how the handle was opened, plus it looks less complex to the human reader of your code.

      Unfortunately, I'm doing this on Win32 :( Win32 doesn't implement the fcntl() function, so I'll go with the 'print nothing' solution for now.

      --DrWhy

      "If God had meant for us to think for ourselves he would have given us brains. Oh, wait..."

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