Walter, I think this is a dmc bug: I found it within the wxWidgets library when a new version of png was introduced.

This is a reduced version of pngrutil.c
I'm compiling it with

dmc -mn -c -opngrutil.obj -g -o+none -D_WIN32_WINNT=0x0400 -I..\..\src\zlib    pngrutil.c

please let me know if you see the bug too, or if i can provide any further information
chris

/* pngrutil.c - utilities to read a PNG file
 *
 * Last changed in libpng 1.2.19 August 19, 2007
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1998-2007 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
 * This file contains routines that are only called from within
 * libpng itself during the course of reading an image.
 */


#include "png.h"

png_charp /* PRIVATE */
png_decompress_chunk( png_structp png_ptr,   int comp_type,
                              /* png_charp chunkdata, png_size_t chunklength,
                              png_size_t prefix_size, png_size_t *newlength */ )
{

      int ret = 0;

      if (ret != 1)
      {

         char umsg[52];

/* IF YOU REMOVE THIS COMMENT IT FAILS AT png_snprintf(umsg, 50,
         "Unknown zTXt compression type %d", comp_type);


        if (ret == 2)
            png_snprintf(umsg, 52,
                "Buffer error in compressed datastream in %s chunk",
                png_ptr->chunk_name);
         else if (ret == 3)
            png_snprintf(umsg, 52,
                "Data error in compressed datastream in %s chunk",
                png_ptr->chunk_name);
         else
            png_snprintf(umsg, 52,
                "Incomplete compressed datastream in %s chunk",
                png_ptr->chunk_name);
         png_warning(png_ptr, umsg);
*/


   }
   else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
   {
      char umsg[50];

      png_snprintf(umsg, 50,
         "Unknown zTXt compression type %d", comp_type);
      png_warning(png_ptr, umsg);
   }
}

chris elliott wrote:
> Walter, I think this is a dmc bug: I found it within the wxWidgets library when a new version of png was introduced.

Please try to reduce it to a standalone code snippet, please.

Walter Bright wrote:
> chris elliott wrote:
>> Walter, I think this is a dmc bug: I found it within the wxWidgets library when a new version of png was introduced.
> 
> Please try to reduce it to a standalone code snippet, please.
I've tried this: dmc -mn -c -g -o+none chris.c

--------------------chris.c----------------------------------
#      define png_snprintf snprintf   /* Added to v 1.2.19 */
#      define png_snprintf2 snprintf
#      define png_snprintf6 snprintf

int main ()
{
      char umsg[50];
      char umsg2[50];
      int comp_type = 10;

/*comment the next line and the second png_snprintf is compiled OK */
      png_snprintf(umsg, 50, "Unknown zTXt compression type %s", "hello");

      png_snprintf(umsg2, 50, "Unknown zTXt compression type %d", comp_type);

}

Thanks!