I'm trying to make my own variant of printf (one that prints into a dynamic array of char) and am having problems with the OutBuffer class.

char[] Fmt(char[] fmtp, ...)
{
  va_list ap;
  ap = cast(va_list)&fmtp;
  ap += fmtp.size;
  printf(fmtp,*(int*)ap); // this works fine
  OutBuffer buf;
  buf.vprintf(fmtp, ap);  // this doesn't work, causes program termination
errorlevel 128
  return buf.toString();  // but if I don't put something into buf, this
crashes!
}

...

printf(Fmt("This is %dth test\n",45)); // should print This is 45th test,
but it just bombs

Am I using OutBuffer wrongly?  Misunderstanding D's va_list?  or what?

If I leave out buf.vprintf(fmtp, ap), I get a crash.  If I leave it in, I
get the exit(128).

Sean

I got this to work but I think it's a sucky kludge as I can't predict how many characters I'll need:

import c.stdio;

char[] Fmt(char[] fmtp, ...)
{
  va_list ap;
  ap = cast(va_list)&fmtp;
  ap += fmtp.size;
  char[] buf;
  buf.length = 1024;
  vsprintf(buf, fmtp, ap);
  buf.length = strlen(buf);
  return buf;
}

"Sean L. Palmer" <seanpalmer@earthlink.net> wrote in message news:acus8q$gna$1@digitaldaemon.com...
> I'm trying to make my own variant of printf (one that prints into a
dynamic
> array of char) and am having problems with the OutBuffer class.
>
> char[] Fmt(char[] fmtp, ...)
> {
>   va_list ap;
>   ap = cast(va_list)&fmtp;
>   ap += fmtp.size;
>   printf(fmtp,*(int*)ap); // this works fine
>   OutBuffer buf;
>   buf.vprintf(fmtp, ap);  // this doesn't work, causes program termination
> errorlevel 128
>   return buf.toString();  // but if I don't put something into buf, this
> crashes!
> }
>
> ...
>
> printf(Fmt("This is %dth test\n",45)); // should print This is 45th test,
> but it just bombs
>
> Am I using OutBuffer wrongly?  Misunderstanding D's va_list?  or what?
>
> If I leave out buf.vprintf(fmtp, ap), I get a crash.  If I leave it in, I
> get the exit(128).
>
> Sean
>
>

"Sean L. Palmer" <seanpalmer@earthlink.net> wrote in message news:acus8q$gna$1@digitaldaemon.com...

> printf(Fmt("This is %dth test\n",45)); // should print This is 45th test,
> but it just bombs
>
> Am I using OutBuffer wrongly?  Misunderstanding D's va_list?  or what?

OutBuffer's buggy. You've got to wait till Walter fixes it... or write your own.