Dan Johnson wrote:
I’m working on compiling APR with mingw. In
include/arch/win32/apr_arch_misc.h there’s the following code starting
at line 132:
#if APR_HAS_ANSI_FS && APR_HAS_UNICODE_FS
#define IF_WIN_OS_IS_UNICODE if (apr_os_level >= APR_WIN_UNICODE)
#define ELSE_WIN_OS_IS_ANSI else
#else APR_HAS_UNICODE_FS
#define IF_WIN_OS_IS_UNICODE
#define ELSE_WIN_OS_IS_ANSI
#endif /* WINNT */
MSVC accepts this code with no complaint, but mingw (rightfully, I
think) generates “warning: extra tokens at end of #else directive.” Can
someone tell me what this code is supposed to mean?
Confusing, eh? I believe the #else is correct, and should have read;
#else /* !APR_HAS_UNICODE_FS || !APR_HAS_ANSI_FS */
and that the VC compiler silently ignored this.
First note the case above;
#if defined(_WIN32_WCE) || defined(WINNT)
#define APR_HAS_ANSI_FS 0
#else
#define APR_HAS_ANSI_FS 1
#endif
...which means _WCE and WINNT need -no- ANSI mode at all (and _WCE has
no Win32FnA flavors, only Win32FnW flavors, e.g. Unicode).
On WIN32, we always define APR_HAS_UNICODE_FS - even on Win9x you can
use the high-bit characters as a faux-utf8.
Let's take a simple snippet from proc_mutex.c ...
#if APR_HAS_UNICODE_FS
IF_WIN_OS_IS_UNICODE
{
hMutex = CreateMutexW(NULL, FALSE, mutexkey);
}
#endif
#if APR_HAS_ANSI_FS
ELSE_WIN_OS_IS_ANSI
{
hMutex = CreateMutexA(NULL, FALSE, mutexkey);
}
#endif
So once it's exclusively set up with APR_HAS_ANSI_FS or else
APR_HAS_UNICODE_FS, the resulting code is faster and smaller,
but will not be portable between 9x and NT. Eg., on any build
with APR_HAS_ANSI_FS and not APR_HAS_UNICODE_FS, the code above
devolves to;
{
hMutex = CreateMutexA(NULL, FALSE, mutexkey);
}
If you build ANSI_FS on NT, your build will only be able to handle
filenames and resources that map to the current console-mode codepage.
E.g., a web server with resources in several languages will likely fail.
OTOH, if you build UNICODE_FS on 9x, your calls to Win32FnW will fail.
So from a mingw perpsective, if you want to build to target the actual
OS you are configuring on, you should always -D WIN32 and set -D WINNT
for exclusively NT builds, -D _WIN32_WCE for exclusively Windows CE,
and you can (unlike the Win32 native build) unset APR_HAS_UNICODE_FS
if you are targetting Win9x only.
Hope this helps.
Bill
