Re: Private or public task ?

[Robert A Duff <bobduff@shell01.TheWorld.com>]

"mkasun@gmail.com" <mkasun@gmail.com> writes:

> Why do people insist that Ada.Text_IO.Put routines are potentially
> blocking.

Because they're talking about the ones that operate on files,
which are the commonly-used ones.  If you say:

    Ada.Text_IO.Put_Line("Hello, world.");

in a protected procedure, that's wrong.  GNAT will often let you
get away with it, but it's still wrong, because Put_Line is
potentially blocking.

Yes, as you quote below, the Get/Put that do parsing/formatting
on strings are not blocking, as you would expect.  But these
are rarely used, so people forget about them.

> From the ARM
>
> Discussion: {AI95-00178-01} Any subprogram in a language-defined input-
> output package that has a file parameter or result or operates on a
> default file is considered to manipulate a file. An instance of a
> language-defined input-output generic package provides subprograms
> that are covered by this rule. The only subprograms in language-
> defined input-output packages not covered by this rule (and thus not
> potentially blocking) are the Get and Put routines that take string
> parameters defined in the packages nested in Text_IO.

- Bob