Re: Problem where a function is invoked once but called twice (when invocation is within an allocator).

[Anh Vo <anhvofrcaus@gmail.com>]

On May 5, 5:49 pm, Rod Kay <rod....@aulace.com> wrote:
> On May 6, 3:07 am, Florian Weimer <f...@deneb.enyo.de> wrote:
>

> > Could you show the -gnatG output as well?
>
> Source recreated from tree for Tester (body)
> --------------------------------------------
>
> with media;
> with media.media__video;
> with opengl;
> with ada.ada__tags;
> with system.system__secondary_stack;
>
> procedure tester is
>    M13b : system__secondary_stack__mark_id :=
>      $system__secondary_stack__ss_mark;
>
>    procedure tester___clean is
>    begin
>       $system__secondary_stack__ss_release (M13b);
>       return;
>    end tester___clean;
> begin
>    the_movie : media.media__video.media__video__view := media.
>      media__video.media__video__new_video__2 ("xyz.avi");
>    [constraint_error when
>      the_movie = null
>      "access check failed"]
>
>    -- Case 1 begins here ...
>    type tester__A3b is access all opengl__image;
>    R4b : constant tester__A3b := media__video__next_frame (the_movie,
>      selfL => 0)'reference;
>    subtype tester__Tcase_1S is opengl__image (R4b.all'first(1) ..
> R4b.all'
>      last(1), R4b.all'first(2) .. R4b.all'last(2));
>    [constraint_error when
>      R4b.all'last(2) >= R4b.all'first(2) and then (R4b.all'first(2) <
>        0 or else R4b.all'last(2) > 65535)
>      "range check failed"]
>    [constraint_error when
>      R4b.all'last(1) >= R4b.all'first(1) and then (R4b.all'first(1) <
>        0 or else R4b.all'last(1) > 65535)
>      "range check failed"]
>    case_1 : opengl__image (R4b.all'first(1) .. R4b.all'last(1),
> R4b.all'
>      first(2) .. R4b.all'last(2)) := R4b.all;
>
>    -- Case 2 begins here ...
>    type tester__A10b is access all opengl__image;
>    R11b : constant tester__A10b := (media__video__next_frame
> (the_movie,
>      selfL => 0))'reference;
>    subtype tester__A9b is opengl__image ((R11b.all)'first(1) ..
> (R11b.all)'
>      last(1), (R11b.all)'first(2) .. (R11b.all)'last(2));
>    [constraint_error when
>      (R11b.all)'last(2) >= (R11b.all)'first(2) and then ((R11b.all)'
>        first(2) < 0 or else (R11b.all)'last(2) > 65535)
>      "range check failed"]
>    [constraint_error when
>      (R11b.all)'last(1) >= (R11b.all)'first(1) and then ((R11b.all)'
>        first(1) < 0 or else (R11b.all)'last(1) > 65535)
>      "range check failed"]
>    case_2 : access opengl.opengl__image := new opengl.opengl__image'(
>      tester__A9b?((media__video__next_frame (the_movie, selfL =>
> 0))));
>    [subtype tester__T6b is access opengl__image]
>    reference tester__T6b
>    null;
>    return;
> at end
>    tester___clean;
> end tester;
>
>    For Case_2, it appears the 1st call to next_Frame is used purely to
> get the bounds of the returned array. The bounds are then used to
> define 'tester__A9b' which is a subtype of opengl.Image of the correct
> size. 'tester__A9b' is then used to convert the result of the 2nd call
> to next_Frame, during allocation.

What compiler do you use? Do you mind to post the complete (minimum
required) source. I would like to see if I get the same result on my
machine.

Anh Vo