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[PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW

phind.uet@gmail.com posted 2 patches 1 month, 3 weeks ago
Maintainers: Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Stefan Weil <sw@weilnetz.de>, Paolo Bonzini <pbonzini@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Kostiantyn Kostiuk <kkostiuk@redhat.com>, Michael Roth <michael.roth@amd.com>
There is a newer version of this series
[PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by phind.uet@gmail.com 1 month, 3 weeks ago 
From: Nguyen Dinh Phi <phind.uet@gmail.com>

Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
_com_util namespace via <comutil.h>. This causes a redefinition
error when building qemu-ga on Windows with these toolchains.

Add a meson check to detect whether ConvertStringToBSTR is already
available, and conditionally compile our fallback implementation
only when the system does not provide one.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
---
 meson.build               | 12 ++++++++++++
 qga/vss-win32/install.cpp |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/meson.build b/meson.build
index c5710a6a47..60a980e610 100644
--- a/meson.build
+++ b/meson.build
@@ -3299,6 +3299,18 @@ endif
 # Detect host pointer size for the target configuration loop.
 host_long_bits = cc.sizeof('void *') * 8
 
+# Detect if ConvertStringToBSTR has been defined in _com_util namespace
+if host_os == 'windows'
+  has_convert_string_to_bstr = cxx.compiles('''
+    #include <comutil.h>
+    int main() {
+        BSTR b = _com_util::ConvertStringToBSTR("test");
+        return b ? 0 : 1;
+    }
+  ''')
+  config_host_data.set('CONFIG_CONVERT_STRING_TO_BSTR', has_convert_string_to_bstr)
+endif
+
 ########################
 # Target configuration #
 ########################
diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
index 7b25d9098b..5b7a8e9bc5 100644
--- a/qga/vss-win32/install.cpp
+++ b/qga/vss-win32/install.cpp
@@ -549,6 +549,7 @@ STDAPI DllUnregisterServer(void)
 
 
 /* Support function to convert ASCII string into BSTR (used in _bstr_t) */
+#ifndef CONFIG_CONVERT_STRING_TO_BSTR
 namespace _com_util
 {
     BSTR WINAPI ConvertStringToBSTR(const char *ascii) {
@@ -566,6 +567,7 @@ namespace _com_util
         return bstr;
     }
 }
+#endif
 
 /* Stop QGA VSS provider service using Winsvc API  */
 STDAPI StopService(void)
-- 
2.43.0
Re: [PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by Pierrick Bouvier 1 month, 3 weeks ago 
On 12/15/25 8:45 AM, phind.uet@gmail.com wrote:
> From: Nguyen Dinh Phi <phind.uet@gmail.com>
> 
> Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
> _com_util namespace via <comutil.h>. This causes a redefinition
> error when building qemu-ga on Windows with these toolchains.
> 
> Add a meson check to detect whether ConvertStringToBSTR is already
> available, and conditionally compile our fallback implementation
> only when the system does not provide one.
> 
> Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
> ---
>   meson.build               | 12 ++++++++++++
>   qga/vss-win32/install.cpp |  2 ++
>   2 files changed, 14 insertions(+)

Thanks for the fix, I was looking at this error.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Re: [PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by Marc-André Lureau 1 month, 3 weeks ago 
Hi

On Mon, Dec 15, 2025 at 8:57 PM <phind.uet@gmail.com> wrote:

> From: Nguyen Dinh Phi <phind.uet@gmail.com>
>
> Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
> _com_util namespace via <comutil.h>. This causes a redefinition
> error when building qemu-ga on Windows with these toolchains.
>
> Add a meson check to detect whether ConvertStringToBSTR is already
> available, and conditionally compile our fallback implementation
> only when the system does not provide one.
>
> Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
> ---
>  meson.build               | 12 ++++++++++++
>  qga/vss-win32/install.cpp |  2 ++
>  2 files changed, 14 insertions(+)
>
> diff --git a/meson.build b/meson.build
> index c5710a6a47..60a980e610 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3299,6 +3299,18 @@ endif
>  # Detect host pointer size for the target configuration loop.
>  host_long_bits = cc.sizeof('void *') * 8
>
> +# Detect if ConvertStringToBSTR has been defined in _com_util namespace
> +if host_os == 'windows'
> +  has_convert_string_to_bstr = cxx.compiles('''
> +    #include <comutil.h>
> +    int main() {
> +        BSTR b = _com_util::ConvertStringToBSTR("test");
> +        return b ? 0 : 1;
> +    }
> +  ''')
> +  config_host_data.set('CONFIG_CONVERT_STRING_TO_BSTR',
> has_convert_string_to_bstr)
> +endif
> +
>  ########################
>  # Target configuration #
>  ########################
> diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
> index 7b25d9098b..5b7a8e9bc5 100644
> --- a/qga/vss-win32/install.cpp
> +++ b/qga/vss-win32/install.cpp
> @@ -549,6 +549,7 @@ STDAPI DllUnregisterServer(void)
>
>
>  /* Support function to convert ASCII string into BSTR (used in _bstr_t) */
> +#ifndef CONFIG_CONVERT_STRING_TO_BSTR
>

I wonder if it could check __MINGW64_VERSION_MAJOR >= 14 instead of adding
a configure-time check.

lgtm anyway
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

 namespace _com_util
>  {
>      BSTR WINAPI ConvertStringToBSTR(const char *ascii) {
> @@ -566,6 +567,7 @@ namespace _com_util
>          return bstr;
>      }
>  }
> +#endif
>
>  /* Stop QGA VSS provider service using Winsvc API  */
>  STDAPI StopService(void)
> --
> 2.43.0
>
>
Re: [PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by Kostiantyn Kostiuk 1 month, 3 weeks ago 
Hi

On Tue, Dec 16, 2025 at 8:26 AM Marc-André Lureau <
marcandre.lureau@redhat.com> wrote:

> Hi
>
> On Mon, Dec 15, 2025 at 8:57 PM <phind.uet@gmail.com> wrote:
>
>> From: Nguyen Dinh Phi <phind.uet@gmail.com>
>>
>> Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
>> _com_util namespace via <comutil.h>. This causes a redefinition
>> error when building qemu-ga on Windows with these toolchains.
>>
>> Add a meson check to detect whether ConvertStringToBSTR is already
>> available, and conditionally compile our fallback implementation
>> only when the system does not provide one.
>>
>> Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
>> ---
>>  meson.build               | 12 ++++++++++++
>>  qga/vss-win32/install.cpp |  2 ++
>>  2 files changed, 14 insertions(+)
>>
>> diff --git a/meson.build b/meson.build
>> index c5710a6a47..60a980e610 100644
>> --- a/meson.build
>> +++ b/meson.build
>> @@ -3299,6 +3299,18 @@ endif
>>  # Detect host pointer size for the target configuration loop.
>>  host_long_bits = cc.sizeof('void *') * 8
>>
>> +# Detect if ConvertStringToBSTR has been defined in _com_util namespace
>> +if host_os == 'windows'
>> +  has_convert_string_to_bstr = cxx.compiles('''
>> +    #include <comutil.h>
>> +    int main() {
>> +        BSTR b = _com_util::ConvertStringToBSTR("test");
>> +        return b ? 0 : 1;
>> +    }
>> +  ''')
>> +  config_host_data.set('CONFIG_CONVERT_STRING_TO_BSTR',
>> has_convert_string_to_bstr)
>> +endif
>> +
>>  ########################
>>  # Target configuration #
>>  ########################
>> diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
>> index 7b25d9098b..5b7a8e9bc5 100644
>> --- a/qga/vss-win32/install.cpp
>> +++ b/qga/vss-win32/install.cpp
>> @@ -549,6 +549,7 @@ STDAPI DllUnregisterServer(void)
>>
>>
>>  /* Support function to convert ASCII string into BSTR (used in _bstr_t)
>> */
>> +#ifndef CONFIG_CONVERT_STRING_TO_BSTR
>>
>
> I wonder if it could check __MINGW64_VERSION_MAJOR >= 14 instead of adding
> a configure-time check.
>

@Peter Maydell <peter.maydell@linaro.org> preferred to avoid specific
version-number checks.
See: https://gitlab.com/qemu-project/qemu/-/issues/3217#note_2935451782

I also preferred the idea of checking the real function present instead of
the version of the component.

Reviewed-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>


>
> lgtm anyway
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>
>  namespace _com_util
>>  {
>>      BSTR WINAPI ConvertStringToBSTR(const char *ascii) {
>> @@ -566,6 +567,7 @@ namespace _com_util
>>          return bstr;
>>      }
>>  }
>> +#endif
>>
>>  /* Stop QGA VSS provider service using Winsvc API  */
>>  STDAPI StopService(void)
>> --
>> 2.43.0
>>
>>
Re: [PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by Pierrick Bouvier 1 month, 3 weeks ago 
On 12/16/25 1:53 AM, Kostiantyn Kostiuk wrote:
> Hi
> 
> On Tue, Dec 16, 2025 at 8:26 AM Marc-André Lureau 
> <marcandre.lureau@redhat.com <mailto:marcandre.lureau@redhat.com>> wrote:
> 
>     Hi
> 
>     On Mon, Dec 15, 2025 at 8:57 PM <phind.uet@gmail.com
>     <mailto:phind.uet@gmail.com>> wrote:
> 
>         From: Nguyen Dinh Phi <phind.uet@gmail.com
>         <mailto:phind.uet@gmail.com>>
> 
>         Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
>         _com_util namespace via <comutil.h>. This causes a redefinition
>         error when building qemu-ga on Windows with these toolchains.
> 
>         Add a meson check to detect whether ConvertStringToBSTR is already
>         available, and conditionally compile our fallback implementation
>         only when the system does not provide one.
> 
>         Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com
>         <mailto:phind.uet@gmail.com>>
>         ---
>           meson.build               | 12 ++++++++++++
>           qga/vss-win32/install.cpp |  2 ++
>           2 files changed, 14 insertions(+)
> 
>         diff --git a/meson.build b/meson.build
>         index c5710a6a47..60a980e610 100644
>         --- a/meson.build
>         +++ b/meson.build
>         @@ -3299,6 +3299,18 @@ endif
>           # Detect host pointer size for the target configuration loop.
>           host_long_bits = cc.sizeof('void *') * 8
> 
>         +# Detect if ConvertStringToBSTR has been defined in _com_util
>         namespace
>         +if host_os == 'windows'
>         +  has_convert_string_to_bstr = cxx.compiles('''
>         +    #include <comutil.h>
>         +    int main() {
>         +        BSTR b = _com_util::ConvertStringToBSTR("test");
>         +        return b ? 0 : 1;
>         +    }
>         +  ''')
>         +  config_host_data.set('CONFIG_CONVERT_STRING_TO_BSTR',
>         has_convert_string_to_bstr)
>         +endif
>         +
>           ########################
>           # Target configuration #
>           ########################
>         diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
>         index 7b25d9098b..5b7a8e9bc5 100644
>         --- a/qga/vss-win32/install.cpp
>         +++ b/qga/vss-win32/install.cpp
>         @@ -549,6 +549,7 @@ STDAPI DllUnregisterServer(void)
> 
> 
>           /* Support function to convert ASCII string into BSTR (used in
>         _bstr_t) */
>         +#ifndef CONFIG_CONVERT_STRING_TO_BSTR
> 
> 
>     I wonder if it could check __MINGW64_VERSION_MAJOR >= 14 instead of
>     adding a configure-time check.
> 
> 
> @Peter Maydell <mailto:peter.maydell@linaro.org> preferred to avoid 
> specific version-number checks.
> See: https://gitlab.com/qemu-project/qemu/-/issues/3217#note_2935451782 
> <https://gitlab.com/qemu-project/qemu/-/issues/3217#note_2935451782>
> 
> I also preferred the idea of checking the real function present instead 
> of the version of the component.
> 
> Reviewed-by: Kostiantyn Kostiuk <kkostiuk@redhat.com 
> <mailto:kkostiuk@redhat.com>>
> 
> 
>     lgtm anyway
>     Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com
>     <mailto:marcandre.lureau@redhat.com>>
> 
>           namespace _com_util
>           {
>               BSTR WINAPI ConvertStringToBSTR(const char *ascii) {
>         @@ -566,6 +567,7 @@ namespace _com_util
>                   return bstr;
>               }
>           }
>         +#endif
> 
>           /* Stop QGA VSS provider service using Winsvc API  */
>           STDAPI StopService(void)
>         -- 
>         2.43.0
> 

When cross-compiling using fedora-win64-cross, it can find the function 
in header but does not link it.

$ podman run --pull newer --init --rm -it -v $(pwd):$(pwd) -w $(pwd) \
docker.io/pbolinaro/qemu-ci:fedora-win64-cross \
bash -cx './configure $QEMU_CONFIGURE_OPTS && ninja -C build install'
...
[4434/4696] Linking target qga/vss-win32/qga-vss.dll
FAILED: qga/vss-win32/qga-vss.dll
x86_64-w64-mingw32-g++ -m64  -o qga/vss-win32/qga-vss.dll 
qga/vss-win32/qga-vss.dll.p/requester.cpp.obj 
qga/vss-win32/qga-vss.dll.p/provider.cpp.obj 
qga/vss-win32/qga-vss.dll.p/install.cpp.obj 
qga/vss-win32/qga-vss.dll.p/vss-debug.cpp.obj 
-Wl,--allow-shlib-undefined -shared ../qga/vss-win32/qga-vss.def 
-Wl,--start-group -Wl,--out-implib=qga/vss-win32/qga-vss.dll.a 
-fstack-protector-strong -Wl,--no-seh -Wl,--nxcompat -Wl,--dynamicbase 
-Wl,--high-entropy-va -fstack-protector-all -fstack-protector-strong 
-Wl,--add-stdcall-alias -Wl,--enable-stdcall-fixup -lws2_32 -lole32 
-loleaut32 -lshlwapi -luuid -lkernel32 -luser32 -lgdi32 -lwinspool 
-lshell32 -lcomdlg32 -ladvapi32 -Wl,--end-group
/usr/lib/gcc/x86_64-w64-mingw32/14.2.1/../../../../x86_64-w64-mingw32/bin/ld: 
qga/vss-win32/qga-vss.dll.p/install.cpp.obj: in function 
`_bstr_t::Data_t::Data_t(char const*)':
/usr/x86_64-w64-mingw32/sys-root/mingw/include/comutil.h:279:(.text+0x1dc8): 
undefined reference to `_com_util::ConvertStringToBSTR(char const*)'
...

Looking into mingw files, the symbol is not there.
$ nm /usr/x86_64-w64-mingw32/sys-root/mingw/lib/lib*.a |
grep -i ConvertStringToBSTR

It's present in header file though:
/usr/x86_64-w64-mingw32/sys-root/mingw/include/comutil.h

Not sure if something is missing in mingw, or if it's missing an 
attribute to say it should be available at runtime only, but in all 
cases, a simple fix to the patch is:

diff --git a/meson.build b/meson.build
index ab19317f5af..113296544c4 100644
--- a/meson.build
+++ b/meson.build
@@ -3261,7 +3261,7 @@ host_long_bits = cc.sizeof('void *') * 8

  # Detect if ConvertStringToBSTR has been defined in _com_util namespace
  if host_os == 'windows'
-  has_convert_string_to_bstr = cxx.compiles('''
+  has_convert_string_to_bstr = cxx.links('''
      #include <comutil.h>
      int main() {
          BSTR b = _com_util::ConvertStringToBSTR("test");

I would recommend to use cxx.links instead of cxx.compiles for now.

Regards,
Pierrick
Re: [PATCH 1/2] qga/vss-win32: Fix ConvertStringToBSTR redefinition with newer MinGW
Posted by NGUYEN DINH PHI 1 month, 3 weeks ago 
On 12/18/2025 2:13 AM, Pierrick Bouvier wrote:
> On 12/16/25 1:53 AM, Kostiantyn Kostiuk wrote:
>> Hi
>>
>> On Tue, Dec 16, 2025 at 8:26 AM Marc-André Lureau 
>> <marcandre.lureau@redhat.com <mailto:marcandre.lureau@redhat.com>> wrote:
>>
>>     Hi
>>
>>     On Mon, Dec 15, 2025 at 8:57 PM <phind.uet@gmail.com
>>     <mailto:phind.uet@gmail.com>> wrote:
>>
>>         From: Nguyen Dinh Phi <phind.uet@gmail.com
>>         <mailto:phind.uet@gmail.com>>
>>
>>         Newer versions of MinGW-w64 provide ConvertStringToBSTR() in the
>>         _com_util namespace via <comutil.h>. This causes a redefinition
>>         error when building qemu-ga on Windows with these toolchains.
>>
>>         Add a meson check to detect whether ConvertStringToBSTR is 
>> already
>>         available, and conditionally compile our fallback implementation
>>         only when the system does not provide one.
>>
>>         Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com
>>         <mailto:phind.uet@gmail.com>>
>>         ---
>>           meson.build               | 12 ++++++++++++
>>           qga/vss-win32/install.cpp |  2 ++
>>           2 files changed, 14 insertions(+)
>>
>>         diff --git a/meson.build b/meson.build
>>         index c5710a6a47..60a980e610 100644
>>         --- a/meson.build
>>         +++ b/meson.build
>>         @@ -3299,6 +3299,18 @@ endif
>>           # Detect host pointer size for the target configuration loop.
>>           host_long_bits = cc.sizeof('void *') * 8
>>
>>         +# Detect if ConvertStringToBSTR has been defined in _com_util
>>         namespace
>>         +if host_os == 'windows'
>>         +  has_convert_string_to_bstr = cxx.compiles('''
>>         +    #include <comutil.h>
>>         +    int main() {
>>         +        BSTR b = _com_util::ConvertStringToBSTR("test");
>>         +        return b ? 0 : 1;
>>         +    }
>>         +  ''')
>>         +  config_host_data.set('CONFIG_CONVERT_STRING_TO_BSTR',
>>         has_convert_string_to_bstr)
>>         +endif
>>         +
>>           ########################
>>           # Target configuration #
>>           ########################
>>         diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/ 
>> install.cpp
>>         index 7b25d9098b..5b7a8e9bc5 100644
>>         --- a/qga/vss-win32/install.cpp
>>         +++ b/qga/vss-win32/install.cpp
>>         @@ -549,6 +549,7 @@ STDAPI DllUnregisterServer(void)
>>
>>
>>           /* Support function to convert ASCII string into BSTR (used in
>>         _bstr_t) */
>>         +#ifndef CONFIG_CONVERT_STRING_TO_BSTR
>>
>>
>>     I wonder if it could check __MINGW64_VERSION_MAJOR >= 14 instead of
>>     adding a configure-time check.
>>
>>
>> @Peter Maydell <mailto:peter.maydell@linaro.org> preferred to avoid 
>> specific version-number checks.
>> See: https://gitlab.com/qemu-project/qemu/-/ 
>> issues/3217#note_2935451782 <https://gitlab.com/qemu-project/qemu/-/ 
>> issues/3217#note_2935451782>
>>
>> I also preferred the idea of checking the real function present 
>> instead of the version of the component.
>>
>> Reviewed-by: Kostiantyn Kostiuk <kkostiuk@redhat.com 
>> <mailto:kkostiuk@redhat.com>>
>>
>>
>>     lgtm anyway
>>     Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com
>>     <mailto:marcandre.lureau@redhat.com>>
>>
>>           namespace _com_util
>>           {
>>               BSTR WINAPI ConvertStringToBSTR(const char *ascii) {
>>         @@ -566,6 +567,7 @@ namespace _com_util
>>                   return bstr;
>>               }
>>           }
>>         +#endif
>>
>>           /* Stop QGA VSS provider service using Winsvc API  */
>>           STDAPI StopService(void)
>>         --         2.43.0
>>
> 
> When cross-compiling using fedora-win64-cross, it can find the function 
> in header but does not link it.
> 
> $ podman run --pull newer --init --rm -it -v $(pwd):$(pwd) -w $(pwd) \
> docker.io/pbolinaro/qemu-ci:fedora-win64-cross \
> bash -cx './configure $QEMU_CONFIGURE_OPTS && ninja -C build install'
> ...
> [4434/4696] Linking target qga/vss-win32/qga-vss.dll
> FAILED: qga/vss-win32/qga-vss.dll
> x86_64-w64-mingw32-g++ -m64  -o qga/vss-win32/qga-vss.dll qga/vss-win32/ 
> qga-vss.dll.p/requester.cpp.obj qga/vss-win32/qga-vss.dll.p/ 
> provider.cpp.obj qga/vss-win32/qga-vss.dll.p/install.cpp.obj qga/vss- 
> win32/qga-vss.dll.p/vss-debug.cpp.obj -Wl,--allow-shlib-undefined - 
> shared ../qga/vss-win32/qga-vss.def -Wl,--start-group -Wl,--out- 
> implib=qga/vss-win32/qga-vss.dll.a -fstack-protector-strong -Wl,--no-seh 
> -Wl,--nxcompat -Wl,--dynamicbase -Wl,--high-entropy-va -fstack- 
> protector-all -fstack-protector-strong -Wl,--add-stdcall-alias -Wl,-- 
> enable-stdcall-fixup -lws2_32 -lole32 -loleaut32 -lshlwapi -luuid - 
> lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lcomdlg32 -ladvapi32 - 
> Wl,--end-group
> /usr/lib/gcc/x86_64-w64-mingw32/14.2.1/../../../../x86_64-w64-mingw32/ 
> bin/ld: qga/vss-win32/qga-vss.dll.p/install.cpp.obj: in function 
> `_bstr_t::Data_t::Data_t(char const*)':
> /usr/x86_64-w64-mingw32/sys-root/mingw/include/comutil.h:279: 
> (.text+0x1dc8): undefined reference to 
> `_com_util::ConvertStringToBSTR(char const*)'
> ...
> 
> Looking into mingw files, the symbol is not there.
> $ nm /usr/x86_64-w64-mingw32/sys-root/mingw/lib/lib*.a |
> grep -i ConvertStringToBSTR
> 
> It's present in header file though:
> /usr/x86_64-w64-mingw32/sys-root/mingw/include/comutil.h
> 
> Not sure if something is missing in mingw, or if it's missing an 
> attribute to say it should be available at runtime only, but in all 
> cases, a simple fix to the patch is:
> 
> diff --git a/meson.build b/meson.build
> index ab19317f5af..113296544c4 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3261,7 +3261,7 @@ host_long_bits = cc.sizeof('void *') * 8
> 
>   # Detect if ConvertStringToBSTR has been defined in _com_util namespace
>   if host_os == 'windows'
> -  has_convert_string_to_bstr = cxx.compiles('''
> +  has_convert_string_to_bstr = cxx.links('''
>       #include <comutil.h>
>       int main() {
>           BSTR b = _com_util::ConvertStringToBSTR("test");
> 
> I would recommend to use cxx.links instead of cxx.compiles for now.
> 
> Regards,
> Pierrick

Hi,
Upon checking, I found that ConvertStringToBSTR has been declared in 
this header file for quite some time; however, the actual definition was 
introduced only in MinGW releases. I will provide an updated version 
that uses linking instead.

Thanks and best regards,
Phi

Patchew 2.1-devel-b67e4c2

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