How to use sprintf

[Steven Schveighoffer]

On Tue, 26 Apr 2011 13:11:20 -0400, Andrej Mitrovic  
<andrej.mitrovich at gmail.com> wrote:

> On 4/26/11, Timon Gehr <timon.gehr at gmx.ch> wrote:
>>> Isn't it dangerous to pass a D string and let the C code overwrite the
>>> string, regardless of char* vs .ptr field?
>>
>> There is a possibility for buffer overflow.
>>
>
> No, I mean the C function will overwrite an immutable string.

D would not allow you to pass a .ptr field of an immutable string, because  
the type would be immutable(char)* and wouldn't implicitly cast to the  
required char* argument.  Casting, however, would mask that problem and  
probably overwrite immutable data (and probably segfault on Linux).   
Another example of why casting is bad.

for example, this should throw an error:

import std.stdio;

void main()
{
    sprintf("buf".ptr, "%d", 12345);
}

-Steve