Re: [rtl] printing float

[Tony Denault <denault@hawaii.edu>]

On Thu, 26 Apr 2001, Frederic Cazenave wrote:

> Hi,
>
> What can I do to print float inside a fp thread ???
> I tryed to do
> 	char f_print[128];
>

After my signature, I'll post a very simple sprintf-like function - Its
very limited, but does floating point values. One of its problems
is that it uses the va_start() family of function. I think these are
non-reentrance macros so you can not do something like this:

int mrt_msg( const char * fmt, ...)
{
   int  l;
   char buf[256];
   va_list argptr;

   va_start( argptr, fmt );
   l = mrt_sprintf( buf, sizeof(buf), argptr );
   va_end( argptr );

   rtf_put( AO_FIFO_OUT_INX, buf, l);
   return l;
}

I ended up having to duplicate the code for mrt_sprint() inside mrt_msg().
Anyone else have a better solution they are willing to post?

Tony

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There is my mrt_sprint():

#include <rtl_fifo.h>
#include <stdarg.h>
#include <string.h>

static char dig[10] = {'0','1','2','3','4','5','6','7','8','9' };

/*--------------------------------------------------------------------
**  mrt_sprintf() - very simple sprintf funciton to format output.
**                  returns strlen(message).
*/
int mrt_sprintf( char * message, int msg_len, const char *format,...)
{

  char buf[128];
  int pos = 0;

  va_list args;

  va_start(args,format);

  while (*format && (pos < msg_len-2)) {
    if (*format == '%'){
      char *b;
      ++format;
      switch(*format) {
      case 's':{
        char *s;
        s = va_arg(args,char *);
        sprintf(buf,"%s",s);
      }break;
      case 'd':{
        int d;
        d = va_arg(args,int);
        sprintf(buf,"%d",d);
      }break;
      case 'x':{
        int d;
        d = va_arg(args,int);
        sprintf(buf,"%x",d);
      }break;
      case 'g':{
        double f;
        int fi, f0, f1, f2;
        char c;
        f = va_arg(args,double);
        if (f <0){
          c = '-';
          f = -f;
        }else{
          c = ' ';
        }
        fi = (int)f;   // integer portion.
        // decmial portion...get index for upto 3 decmial places.
        f = f - fi;
        f0 = f*10;   f0 %= 10;
        f1 = f*100;  f1 %= 10;
        f2 = f*1000; f2 %= 10;
        sprintf(buf,"%c%d.%c%c%c", c, fi, dig[f0], dig[f1], dig[f2]);
      }break;
      default:
        sprintf(buf,"(Unsupported format %c)",*format);
      }

      ++format;
      b = buf;
      while (*b && pos < msg_len-2){
        message[pos] = *b;
        ++b;
        ++pos;
      }
    }else{
      message[pos] = *format;
      ++pos;
      ++format;
    }
  }

  message[pos] = 0;
  va_end(args);

  return pos;
}

/** done **/