Where is SetOaNoCache defined?

问题

Attempting to disable BSTR caching:

SetOaNoCache();

VC++ compiler build output:

• 'SetOaNoCache': identifier not found

Don't want to use:

• OANOCACHE=1

Question:

• Where is SetOaNoCache defined - header file?

回答1:

It is not defined in a header file, it is in OLEAUT32.dll. You can call it like this:

typedef int (*SETOANOCACHE)(void);

void DisableBSTRCache()
{
    HINSTANCE hLib = LoadLibrary("OLEAUT32.DLL");
    if (hLib != NULL)
    {
        SETOANOCACHE SetOaNoCache = (SETOANOCACHE)GetProcAddress(hLib, "SetOaNoCache");
        if (SetOaNoCache != NULL)
            SetOaNoCache();
        FreeLibrary(hLib);
    }
}

回答2:

It's not. From the Win32 API library shipped with C++ Builder:

Requirements

Windows XP: Requires Windows XP Service Pack 2 or later.

Windows 95/98: Not supported.

Header: Not supplied. Declare prototype as shown.

Library: Use oleaut32.lib.

The prototype as shown:

inline void TurnOffCache ()
{
// Function prototype.
extern "C" SetOaNoCache(); 
// Turn off BSTR caching.
SetOaNoCache();
}

来源：https://stackoverflow.com/questions/553846/where-is-setoanocache-defined