[plt-scheme] printing question

Chongkai Zhu <czhu at cs.utah.edu> wrote:
> 
> Sorry but scheme_char_string_to_byte_string might trig the GC, so what
> I just suggested is wrong. You might consider first getting
> SCHEME_CHAR_STR_VAL, and then using scheme_utf8_encode functions,
> which are described in section 11 of "inside mzscheme" doc to get C
> char*.

Thank you, that makes sense.  Turning off GC hadn't made sense to me,
which I guess is why I was stuck.  But tell me, all I want to do is to
print out a formatted scheme string, and this seems way more trouble
than it's worth.  But I had tried using scheme_printf(), but with this:

    if (SCHEME_CHAR_STRINGP(argv[1])) {
      scheme_printf("Waiting to start: ~a~n",22,1,&argv[1]);

I get this:

   > (trigger "jello")
   printf: format string requires 0 arguments, given 1; arguments were: "jello"

Do I need to escape the tildes in some way?  Or is there something else
dumb I'm doing here?

Many thanks,

 -tom

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