The program exits unexpectedly

[Ali Çehreli via Digitalmars-d-learn]

On 12/09/2016 08:50 AM, unDEFER wrote:
 > On Friday, 9 December 2016 at 14:29:38 UTC, unDEFER wrote:
 >> I'm afraid that the problem that my program wants to say something,
 >> but there is no "flush" so message leaves in the buffer.
 >
 > I have found, it was code like:
 >
 > string path = "C:";
 > string parent = path[0..path.lastIndexOf("\\")];

That's a bug because you're not checking the return value of 
lastIndexOf. According to its documentation, lastIndexOf returns -1 if 
it fails to find the needle:

   http://dlang.org/phobos/std_string.html#.lastIndexOf

     ptrdiff_t found = path.lastIndexOf("\\");
     if (found == -1) {
         // Not found
     }
     else {
         // Now we can use it:
         string parent = path[0..path.lastIndexOf("\\")];
         // ...
      }

The added complication is the fact that ptrdiff_t can be converted to 
size_t and you get a huge string when doing path[0..path.lastIndexOf("\\")]

Do you have boundschecking turned off? It should catch such an error.

 > And in mini program it works and shows diagnostic message.
 > Where my diagnostic message in more complicate program???

Assuming boundschecking is turned off, I think you get unlucky in the 
mini program and happen to hit a '\0' byte.

Ali