c - 获取属性的日期值

我现在正在写一个C程序，它必须做WMI查询。
我可以不费吹灰之力地发出一个查询，但是当从变量中检索属性值时，就变得非常困难了。
我有一个巨大的开关盒，对于每种情况，我只想wprintf值（最终目的是检索wchar_t字符串中的值）。
到目前为止，对于integer类型来说，这并不难，但是对于datetime类型，我一点都没有。
下面是我正在研究的示例（为了便于理解，没有函数检查，但是我做了：

typedef struct cpwmi {
    IWbemLocator         *locator;
    IWbemServices        *services;
    IEnumWbemClassObject *results;
    IWbemClassObject     *result;
} cpwmi_s;

void CpWmi_Constructor(cpwmi_s *self)
{
    self->locator = NULL;
    self->services = NULL;
    self->results = NULL;
    self->result = NULL;
}

void CpWmi_Destructor(cpwmi_s *self)
{
    if (self->result) {
        self->result->lpVtbl->Release(self->result);
    }
    if (self->results) {
        self->results->lpVtbl->Release(self->results);
    }
    if (self->services) {
        self->services->lpVtbl->Release(self->services);
    }
    if (self->locator) {
        self->locator->lpVtbl->Release(self->locator);
    }
}


void CpWmi_MinimalExample(cpwmi_s *self)
{
    // Connection
    CoCreateInstance(&CLSID_WbemLocator, NULL, CLSCTX_INPROC_SERVER, &IID_IWbemLocator, &self->locator);

    BSTR ressource = SysAllocString(L"ROOT\\CIMV2");
    self->locator->lpVtbl->ConnectServer(self->locator, ressource, NULL, NULL, NULL, 0, NULL, NULL, &self->services);
    SysFreeString(ressource);

    // Issue WMI query
    BSTR query = SysAllocString(L"SELECT ReleaseDate FROM Win32_BIOS");
    BSTR language = SysAllocString(L"WQL");
    self->services->lpVtbl->ExecQuery(self->services, language, query, WBEM_FLAG_BIDIRECTIONAL, NULL, &self->results);
    SysFreeString(query);
    SysFreeString(language);

    // Go to first result
    ULONG   count = 0;
    self->results->lpVtbl->Next(self->results, WBEM_INFINITE, 1, &self->result, &count);

    // Get propperty's value
    BSTR    propertyName = SysAllocString(L"ReleaseDate");
    VARIANT propertyValue;
    CIMTYPE propertyType;
    self->result->lpVtbl->Get(self->result, propertyName, 0, &propertyValue, &propertyType, 0);
    wprintf(L"%s: ", propertyName);

    if (propertyValue.vt != VT_NULL && propertyValue.vt != VT_EMPTY) {
        switch (propertyType) {
            /* Many case here */
        case CIM_DATETIME:
            wprintf(L"%f", propertyValue.date);
            break;
        }
    }
    VariantClear(&propertyValue);
    wprintf(L"\n");
}

int main(void)
{
    cpwmi_s wmi;

    CpWmi_Constructor(&wmi);

    // initialize COM
    CoInitializeEx(NULL, COINIT_MULTITHREADED);
    CoInitializeSecurity(NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_DEFAULT, RPC_C_IMP_LEVEL_IMPERSONATE, NULL, EOAC_NONE, NULL);

    CpWmi_MinimalExample(&wmi);

    CpWmi_Destructor(&wmi);

    // unwind everything else we've allocated
    CoUninitialize();

    printf("Stop\n");
    getchar();
    return;
}

我想有点像
发布日期：20140401000000.000000+000
但我最终
发布日期：92559592126069970772275711289628980735378270670621907468943360.000000
我一定是看错了msdn文档，或者不知道如何搜索/读取，因为到目前为止，我还不知道如何在C中进行搜索/读取！
我还担心CIM_REFERENCE_TYPE、CIM_OBJECT_TYPE等等。
有没有人有暗示或者知道要这么做？

最佳答案

propertyValue.date是double，它需要"%g"打印格式，但可能无效。改为尝试bstrVal值：

case CIM_DATETIME:
    //wprintf(L"%g\n", propertyValue.date);
    wprintf(L"%s\n", propertyValue.bstrVal);
    break;

注意，在调试模式下，您可以将光标移到propertyValue上，它应该显示propertyValue中包含的值