Re: all OS functions should be "nothrow @trusted @nogc"

[ag0aep6g via Digitalmars-d]

On 07/27/2017 03:24 PM, Moritz Maxeiner wrote:
--- null.d ---
version (linux):
import core.stdc.stdio : FILE;
import core.sys.linux.sys.mman;

extern (C) @safe int fgetc(FILE* stream);

void mmapNull()
{
     void* mmapNull = mmap(null, 4096, PROT_READ | PROT_WRITE, 
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED | MAP_POPULATE, -1, 0);
     assert (mmapNull == null, "Do `echo 0 > /proc/sys/vm/mmap_min_addr` 
as root");
     *(cast (char*) null) = 'D';
}

void nullDeref() @safe
{
     fgetc(null);
}

void main(string[] args)
{
     mmapNull();
     nullDeref();
}
---

For some fun on Linux, try out
# echo 0 > /proc/sys/vm/mmap_min_addr
$ rdmd null.d

The gist of this is that Linux can be configured so that null can be a 
valid pointer. Right?

That seems pretty bad for @safe at large, not only when C functions are 
involved.