Re: dup2() on stdout [or using disp() on another file stream]

[Joao Cardoso]

"John W. Eaton" wrote:

> On 16-Oct-1999, Joao Cardoso <address@hidden> wrote:
>
> | How can I use 'disp' on a file stream other than 'stdout'?
> |
> | 'disp' is an easy and nice way to print matrices, without the need to
> | create a format string to use on 'fprintf'. I would like to:
> |
> |      f_name = tmpnam
> |      fout = fopen(f_name,"w");
> |      disp(fout, rand(3))        <--- not supporred
> |      fclose(fout)
> |
> | When I tried to use:
> |
> |     f_name = tmpnam
> |     fout = fopen(f_name,"w");
> |     old = fopen("old","w");
> |
> |     dup2(stdout, old); # save old stdout on 'old'?
> |     dup2(fout, stdout); # use new stdout
> |
> |     disp(rand(3))
> |
> |     dup2(old, stdout);  #revert to saved stdout?
> |
> | I wasn't able to revert stdout to the original stdout. what is wrong? I
> | can't 'fclose(stdout)', either.

...

> Perhaps it would be better to just implement an fdisp() function that
> does what you want?  Or, in the current bleeding-edge sources, Octave
> has a `file' data type and a C++-like output operator, so you can
> write:
>
>   file = fopen (fname, "w");
>   file << rand (3);

this is fine. Thanks.

> to print a formatted matrix to a file.
>
> (I'm not sure that the `<<' operator is a good idea though -- this feature is
> still experimental.)

yes, too much C++ alike for Octave, I think. But the general idea is fine, and
after all Octave future is not to be a static one, neither whatever Matlab
designers think that is best appropriate.

Joao

>
>
> jwe

--
Joao Cardoso                |   e-mail: address@hidden
INESC, R. Jose Falcao 110   |   tel:    + 351 2 2094322
4050 Porto, Portugal        |   fax:    + 351 2 2008487





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