Question

When a program accesses files, uses system(), etc., how and where is the current working directory of that program physically known/stored? Since logically the working directory of a program is similar to a global variable, it should ideally be thread-local, especially in languages like D where “global” variables are thread-local by default. Would it be possible to make the current working directory of a program thread-local?

Note: If you are not familiar with D specifically, even a language-agnostic answer would be useful.

Answer 1

Current directory is maintained by the OS, not by language or framework. See description of GetCurrentDirectory WinAPI function for details.

From description:

Multithreaded applications and shared
library code should not use the
GetCurrentDirectory function and
should avoid using relative path
names. The current directory state
written by the SetCurrentDirectory
function is stored as a global
variable in each process, therefore
multithreaded applications cannot
reliably use this value without
possible data corruption from other
threads that may also be reading or
setting this value.