core.sys.posix.unistd link error

[Ruslan Mullakhmetov]

I found where the problem is.

I used a system call (external C function) in class ctor. then I 
declared global variable of this class and INITIALZIED that 
variable inplace. If i move initalization in module static this() 
everything compiles.

the code is:

incorrect version:
http://dpaste.com/hold/1391530/

correct:
http://dpaste.com/hold/1391523/


But now i need to sort out what the difference between
// global scope

int a = 10;

and

int a;

static this()
{
  a = 10;
}


I appreciate if somebody give a link or chapter number where to 
read.