Comparing two GUID's in C

Comparing two GUID's in C

I am working on a C program from Visual Studio 2010. I need to create
GUID's and then compare.
I am including "#include guiddef.h" in my progarm.
Following is the code snippet but I keep on getting errors when I compile
my code.
//mainGUID is assign value in the program
GUID mainGUID;
//Function call which compares passed GUID with the mainGUID
int CheckGUID(GUID guid)
{
if(IsEqualGUID(guid,mainGUID))
return 1;
else
return 0;
}
I get following error
Error 3 error C2172: 'memcmp' : actual parameter is not a pointer :
parameter 1
Error 3 error C2172: 'memcmp' : actual parameter is not a pointer :
parameter 2
Not sure what is going on.