"warning: implicit conversion from matrix to sq_string" message

[Sergei Steshenko]

Hello,

I am working on 'pkg.m' in octave-3.4.2, and I have this piece of code:

        fprintf(stderr, "CHECKPOINT 2a\n");
        fprintf(stderr, "%s",  toascii(output));
        fprintf(stderr, "CHECKPOINT 2b\n");

producing the following output:

"
CHECKPOINT 2a
warning: implicit conversion from matrix to sq_string
checking for pkg-config... 
/mnt/sdb8/sergei/AFSWD_debug/20110601/pkg-config-0.25/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for GINAC... yes
configure: creating ./config.status

  "$prefix" is 
/mnt/sdb8/sergei/AFSWD_debug/20110601/octave-3.4.2/share/octave/packages/symbolic-1.0.9
  "$exec_prefix" is ${prefix}


find . -name NOINSTALL -print    # shows which toolboxes won't be installed

CHECKPOINT 2b
".

In the above output one can see

"
warning: implicit conversion from matrix to sq_string
".

The above warning is also produced when I simply have

        fprintf(stderr, "%s",  output);

- I hoped 'toascii' would remove the warning.

Is this warning my bug, i.e. I am forcing 'octave' to perform an implicit
conversion, but there is a way to perform an explicit conversion and
eliminate the warning ? If so, what conversion should I use ?

Or is it an 'octave' bug ?

Thanks,
  Sergei.