Hannu Krosing <hannu@tm.ee> writes:
> What would your opinion be of some hack with macros, like
> #if (Win32 or THREADED)
> #define GLOBAL_ pg_globals.
> #else
> #define GLOBAL_
> #endif
> and then use global variables as
> GLOBAL_globvar
> At least in my opinion that would increase both readability and
> maintainability.
From a code readability viewpoint this is not at all better than just
moving everything to pg_globals. You're only spelling "pg_globals."
a little differently. And it introduces twin possibilities for error:
omitting GLOBAL_ (if you're a Unix developer) or writing
pg_globals. explicitly (if you're a Win32 guy). I suppose these errors
would be caught as soon as someone tried to compile on the other
platform, but it still seems like a mess with little redeeming value.
I think there had been some talk of
#if Win32
#define myvar pg_globals.f_myvar
#else
static int myvar;
#endif
which seems a more effective use of macros --- it would at least allow
the code to be written without explicit awareness of the special status
of the variable. Still seems like a maintenance nightmare though.
The real problem with airily saying "we'll just move that variable to
pg_globals" is that it falls down the instant that you consider
non-scalar variables. What if it's a pointer to a palloc'd structure?
Sure we can get around this, but not transparently.
regards, tom lane
