Windows.h CONDITION_VARIABLE causes exception (C/C++)

Question

I'm having trouble with very basic Windows programming, implementing a simple producer/consumer system.

My struct:

typedef struct FILE_BUFFER { //Circular buffer of max size BUF_SIZE
    INT count;            //buffer size 
    LPTSTR buf[BUF_SIZE]; //actual buffer of file names

    BOOL stopRequested; //Exit flag

    LPCRITICAL_SECTION lock; //Synch stuff
    PCONDITION_VARIABLE notEmpty;
    PCONDITION_VARIABLE notFull;
}FILE_BUFFER;

FILE_BUFFER fb;

my init function (ran in main thread)

VOID init() {
    fb.stopRequested = FALSE;
    fb.count = 0;
    InitializeCriticalSection(fb.lock);
    InitializeConditionVariable(fb.notEmpty);
    InitializeConditionVariable(fb.notFull);
}

The init function cause exception to be thrown on the InitializeConditionVariable instruction, of type Access Violation (ntdll.dll).

I'm using Visual Studio 2017 and compiling for Windows x64

Thanks

Answer 1

You are passing uninitialized pointers as parameters to InitializeCriticalSection and InitializeConditionVariable. You should allocate appropriate structures and pass a pointer to them instead:

CRITICAL_SECTION lock; //Synch stuff
CONDITION_VARIABLE notEmpty;
CONDITION_VARIABLE notFull;

...

InitializeCriticalSection(&(fb.lock));
InitializeConditionVariable(&(fb.notEmpty));
InitializeConditionVariable(&(fb.notFull));