#include <stdio.h>
#include <sys/types.h>

typedef char* png_charp;
typedef const char* png_const_charp;

/* Utility to safely appends strings to a buffer.  This never errors out so
 * error checking is not required in the caller.
 */
size_t png_safecat(png_charp buffer,
                   size_t bufsize,
                   size_t pos,
                   png_const_charp string)
{
   if (buffer != NULL && pos < bufsize) {
      if (string != NULL) {
         while (*string != '\0' && pos < bufsize-1)
           { buffer[pos++] = *string++; }
      }
      buffer[pos] = '\0';
   }
   return pos;
}

int main() {
  size_t pos = 0;
  char number_buf[5]; /* enough for a four-digit year */ /* FLTK Issue #296 */
  png_safecat(number_buf, sizeof(number_buf), pos, "ABC");
  printf("RESULT: '%s'\n", number_buf);
  return 0;
}