mingw: replace mingw_startup() hack

Git for Windows has special code to retrieve the command-line parameters
(and even the environment) in UTF-16 encoding, so that they can be
converted to UTF-8. This is necessary because Git for Windows wants to
use UTF-8 encoded strings throughout its code, and the main() function
does not get the parameters in that encoding.

To do that, we used the __wgetmainargs() function, which is not even a
Win32 API function, but provided by the MINGW "runtime" instead.

Obviously, this method would not work with any compiler other than GCC,
and in preparation for compiling with Visual C++, we would like to avoid
precisely that.

Lucky us, there is a much more elegant way: we can simply implement the
UTF-16 variant of `main()`: `wmain()`.

To make that work, we need to link with -municode. The command-line
parameters are passed to `wmain()` encoded in UTF-16, as desired, and
this method also works with GCC, and also with Visual C++ after
adjusting the MSVC linker flags to force it to use `wmain()`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 11 deletions

diff --git a/compat/mingw.h b/compat/mingw.h
index 593bdbffe6..210f1b01a8 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -562,18 +562,18 @@ int xwcstoutf(char *utf, const wchar_t *wcs, size_t utflen);
 extern CRITICAL_SECTION pinfo_cs;
 
 /*
- * A replacement of main() that adds win32 specific initialization.
+ * Git, like most portable C applications, implements a main() function. On
+ * Windows, this main() function would receive parameters encoded in the
+ * current locale, but Git for Windows would prefer UTF-8 encoded  parameters.
+ *
+ * To make that happen, we still declare main() here, and then declare and
+ * implement wmain() (which is the Unicode variant of main()) and compile with
+ * -municode. This wmain() function reencodes the parameters from UTF-16 to
+ * UTF-8 format, sets up a couple of other things as required on Windows, and
+ * then hands off to the main() function.
  */
-
-void mingw_startup(void);
-#define main(c,v) dummy_decl_mingw_main(void); \
-static int mingw_main(c,v); \
-int main(int argc, const char **argv) \
-{ \
-	mingw_startup(); \
-	return mingw_main(__argc, (void *)__argv); \
-} \
-static int mingw_main(c,v)
+int wmain(int argc, const wchar_t **w_argv);
+int main(int argc, const char **argv);
 
 /*
  * Used by Pthread API implementation for Windows