Re: problem with output of the program on different OS

Richard Heathfield said:

<snip>
 
> If I get the time, I'll continue this review exercise later.

Well, I don't hold out a lot of hope for this review, judging by the OP's 
reply to the first part thereof ("I think this is not the problem", for 
instance, shows a remarkable talent for disregarding general-principle 
comments simply because they don't appear to explain the immediate cause 
of the immediate segfault - if ever there were a short-sighted approach to

debugging, this has to be it).

Nevertheless, let's press on for now.

I fixed the scanfs in initialize_radar(), checking the return values and 
returning FAILURE if they were incorrect. (As mentioned in my earlier 
article, I also C90ified and re-indented the code, purely for my own 
convenience.) The function now looks like this:

int initialize_radar(bbox b,
                     radar_detector * radar)
{
  int rc = SUCCESS;
  vector *pointinarray = NULL;
  int i;
  unsigned long int ray_count;

  radar->maxP = b.maxB;
  radar->minP = b.minB;
  radar->maxP.z = radar->minP.z = b.minB.z - 1000;

  printf
    ("Enter the frequency of the electromagnetic rays to be fired\n");
  if(scanf("%le", &radar->frequency) != 1)
  {
    rc = FAILURE;
  }
  else
  {
    radar->wavenumber = 2 * M_PI * radar->frequency / VELOCITY;

    printf("Enter the amplitude of electric field\n");
    if(scanf("%le", &radar->E0) != 1)
    {
      rc = FAILURE;
    }
  }

  if(rc == SUCCESS)
  {
    printf("Enter the number of electromagnetic rays to be fired\n");
    if(scanf("%lu", &radar->numberofrays) != 1)
    {
      rc = FAILURE;
    }
  }

  if(rc == SUCCESS)
  {
    real(radar->E_incident) = 0;
    imag(radar->E_scattered) = 0;

    i =
      gen_grid_points(&pointinarray, &radar->numberofrays, b.maxB.x,
                      b.minB.x, b.maxB.y, b.minB.y, b.minB.z - 1000);
    if(i == FAILURE)
    {
      rc = FAILURE;
    }
  }
  if(rc == SUCCESS)
  {
    ray_count = radar->numberofrays;
    radar->raylist = malloc(ray_count * sizeof (ray));
    if(radar->raylist == NULL)
    {
      perror("malloc has failed");
      rc = FAILURE;
    }
  }

  if(rc == SUCCESS)
  {
    for(ray_count = 0; ray_count < radar->numberofrays; ray_count++)
    {
      radar->raylist[ray_count].origin = pointinarray[ray_count];
      radar->raylist[ray_count].direction.x = 0;
      radar->raylist[ray_count].direction.y = 0;
      radar->raylist[ray_count].direction.z = 1;
      radar->raylist[ray_count].depth = 0;
      radar->raylist[ray_count].pathlength = DBL_MAX;
      radar->raylist[ray_count].child = NULL;
      real(radar->raylist[ray_count].efield) = radar->E0;
      imag(radar->raylist[ray_count].efield) = 0;
    }
  }

  free(pointinarray);

  return rc;

}

This source file (radar.c) now gives just two diagnostic messages, both to

do with passing an unsigned long int to sqrt. (Yes, I killed my insertion 
of assert(*numpoints >= 0, now that I realise *numpoints has unsigned 
integer type.

Continuing on my quest to get the diagnostic count down a bit, I moved on 
to reader.c. Simply moving the definitions of tem****ary vectors up to the 
top of the function, I made the code C90-compatible. The remaining 
warnings are:

reader.c:68: warning: passing arg 2 of `calloc' as unsigned due to 
prototype
reader.c:69: warning: passing arg 2 of `calloc' as unsigned due to 
prototype
reader.c:109: warning: enumeration value `LAST_LINE' not handled in switch

Although I don't like the first two, I can live with them if you can - the

alternative (i.e. to use unsigned types for nvert and ntri) may be more 
painful to fix than is practical (I haven't delved).

The last one, I leave in your hands. I'm not making any huge attempt to 
understand the program here - I'm just looking at the C.

I needed to C90ify the test.c file, changing a comment to /* style */ and 
moving a definition up a bit. The reflection.c file also needed some 
comment-fixing.

Now it compiles. It doesn't /link/, but that's my makefile's problem, not 
yours. So let's run it:

$ ./raytrace 
Enter the frequency of the electromagnetic rays to be fired

Well, I have no idea what to type here, so I just entered 0 for
everything, 
and lo and behold, I got an assertion failure:

raytrace: radar.c:49: gen_grid_points: Assertion `numpointsx > 1' failed.

I added this assertion because your code assumed that numpointsx could not

be 1 or lower. That assumption is clearly wrong.

I suggest you fix this (by validating your data before passing it to the 
function that needs it to be > 1). If the code continues to give problems 
after that's fixed, show us the fixed code so that we know that this 
particular problem is known not to be a candidate any longer.

-- 
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www.
+rjh@[EMAIL PROTECTED]
 users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999