#include <VersionHelpers.h>

#endif

/* remove some flags on older version Windows during run-time.

https://msdn.microsoft.com/en-us/library/windows/desktop/ms738596.aspx */

typedef struct {

DWORD build_number; /* available starting with this Win10 BuildNumber */

const char flag_name[20];

} FlagRuntimeInfo;

/* IMPORTANT: make sure the list ordered by descending build_number */

static FlagRuntimeInfo win_runtime_flags[] = {

/* available starting with Windows 10 1703 */

{15063, "TCP_KEEPCNT"},

/* available starting with Windows 10 1607 */

{14393, "TCP_FASTOPEN"}

};

static void

remove_unusable_flags(PyObject *m)

{

PyObject *dict;

OSVERSIONINFOEX info;

DWORDLONG dwlConditionMask;

dict = PyModule_GetDict(m);

if (dict == NULL) {

return;

}

/* set to Windows 10, except BuildNumber. */

memset(&info, 0, sizeof(info));

info.dwOSVersionInfoSize = sizeof(info);

info.dwMajorVersion = 10;

info.dwMinorVersion = 0;

/* set Condition Mask */

dwlConditionMask = 0;

VER_SET_CONDITION(dwlConditionMask, VER_MAJORVERSION, VER_GREATER_EQUAL);

VER_SET_CONDITION(dwlConditionMask, VER_MINORVERSION, VER_GREATER_EQUAL);

VER_SET_CONDITION(dwlConditionMask, VER_BUILDNUMBER, VER_GREATER_EQUAL);

for (int i=0; i<sizeof(win_runtime_flags)/sizeof(FlagRuntimeInfo); i++) {

info.dwBuildNumber = win_runtime_flags[i].build_number;

/* greater than or equal to the specified version?

Compatibility Mode will not cheat VerifyVersionInfo(...) */

if (VerifyVersionInfo(

&info,

VER_MAJORVERSION|VER_MINORVERSION|VER_BUILDNUMBER,

dwlConditionMask)) {

break;

}

else {

if (PyDict_GetItemString(

dict,

win_runtime_flags[i].flag_name) != NULL) {

PyDict_DelItemString(

dict,

win_runtime_flags[i].flag_name);

}

}

}

}

#endif

#include <stddef.h>

#if defined(USE_GETHOSTBYNAME_LOCK) || defined(USE_GETADDRINFO_LOCK)

netdb_lock = PyThread_allocate_lock();

#endif

#ifdef MS_WINDOWS

/* removes some flags on older version Windows during run-time */

remove_unusable_flags(m);

#endif

return m;

}