Why does this work?

[Mike L.]

Denis Koroskin Wrote:

> Mike L. Wrote:
> 
> > I saved and compiled the code given as getenv.d on the page http://www.digitalmars.com/d/archives/digitalmars/D/learn/623.html but I'm not entirely sure why it works.
> > 
> > The reasons that I don't understand it are:
> > 1. GetEnvironmentStringsA() and the other functions aren't mentioned in std/c/windows/windows.d .
> 
> It is not defined int std.c.windows.windows, that's why it is defined in the code itself:
> 
> # // function retrieves the environment variables for the current process.
> # extern( Windows ) LPVOID GetEnvironmentStringsA();
> #  
> 
> > and I can compile it with a simple "dmd getenv.d" without passing any other object files or libraries. If it's not in windows.d, why is windows.d even imported?
> > 
> 
> std.c.windows.windows is imported so that compiler knows about LPSTR, LPVOID, BOOL etc.
> 
> > 2. MSDN says that GetEnvironmentStringsA() returns LPTCH but getenv.d's version returns LPVOID.
> 
> That's true, you should update function's return type and remove unneccessary casts:
> 
> extern( Windows ) LPTSTR GetEnvironmentStringsA();
> ...
> for (lpszVariable = lpvEnv; *lpszVariable; lpszVariable++)

Thanks for your response. Could you tell me what the compiler is linking to that contains GetEnvironmentStringsA() (and others) and how the compiler knows to do this?