[PATCH 0/1] MR5254: msvcrt: Only print __stdio_common_vfscanf() FIXME once.

[Aida Jonikienė (＠DodoGTA)]

One game spams this function so much that it becomes the single biggest
contributor to the Wine log size.

[PATCH 1/1] msvcrt: Only print __stdio_common_vfscanf() FIXME once.

[Aida Jonikienė]

From: Aida Jonikienė

One game spams this function so much that it becomes the single biggest
contributor to the Wine log size.
---
 dlls/msvcrt/scanf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/msvcrt/scanf.c b/dlls/msvcrt/scanf.c
index 89575101471..d71a9c5c1d4 100644
--- a/dlls/msvcrt/scanf.c
+++ b/dlls/msvcrt/scanf.c
@@ -710,7 +710,9 @@ int CDECL __stdio_common_vfscanf(unsigned __int64 options,
                                        _locale_t locale,
                                        va_list valist)
 {
-    if (options & ~_CRT_INTERNAL_SCANF_SECURECRT)
+    static unsigned int once;
+
+    if ((options & ~_CRT_INTERNAL_SCANF_SECURECRT) && !once++)
         FIXME("options %#I64x not handled\n", options);
     if (options & _CRT_INTERNAL_SCANF_SECURECRT)
         return vfscanf_s_l(file, format, locale, valist);

[Piotr Caban (＠piotr)]

Piotr Caban (@piotr) commented about dlls/msvcrt/scanf.c:
>                                     _locale_t locale,
>                                     va_list valist)
>
> {
> - if (options & ~_CRT_INTERNAL_SCANF_SECURECRT)
> - static unsigned int once;
> -
> - if ((options & ~_CRT_INTERNAL_SCANF_SECURECRT) && !once++)
>     FIXME("options %#I64x not handled\n", options);

What's the value of flag that we don't support? Do you know how hard it is to implement missing flag instead of disabling FIXME message?

[Aida Jonikienė (＠DodoGTA)]

On Thu Mar  7 11:13:04 2024 +0000, Piotr Caban wrote:
> What's the value of flag that we don't support? Do you know how hard it
> is to implement missing flag instead of disabling FIXME message?

It's 0x2 (`_CRT_INTERNAL_SCANF_LEGACY_WIDE_SPECIFIERS`)

Looking at the Wine source code this flag is used by the scanf(_s) and fscanf(_s) functions (after some searches I discovered it's used to enable the pre-C99 format specifier behavior)

[Piotr Caban (＠piotr)]

On Thu Mar  7 11:26:34 2024 +0000, Aida Jonikienė wrote:
> It's 0x2 (`_CRT_INTERNAL_SCANF_LEGACY_WIDE_SPECIFIERS`)
> Looking at the Wine source code this flag is used by the scanf(_s) and
> fscanf(_s) functions (after some searches I discovered it's used to
> enable the pre-C99 format specifier behavior)

The flag has only effect on wide scanf and can be ignored in __stdio_common_vfscanf.

Please change the code to:
```c
        if (options & ~(_CRT_INTERNAL_SCANF_SECURECRT | _CRT_INTERNAL_SCANF_LEGACY_WIDE_SPECIFIERS))
            FIXME("options %#I64x not handled\n", options);
```