Pointer-related macros

Because different platforms and compilers have different ways of dealing with different types of pointers, Cryptoki requires the following 6 macros to be set outside the scope of Cryptoki:

CK_PTR

CK_PTR is the "indirection string" a given platform and compiler uses to make a pointer to an object. It is used in the following fashion:
typedef CK_BYTE CK_PTR CK_BYTE_PTR;

CK_DEFINE_FUNCTION

CK_DEFINE_FUNCTION(returnType, name), when followed by a parentheses-enclosed list of arguments and a function definition, defines a Cryptoki API function in a Cryptoki library. returnType is the return type of the function, and name is its name. It is used in the following fashion:

CK_DEFINE_FUNCTION(CK_RV, C_Initialize)(   CK_VOID_PTR pReserved  )  {  ...  }

CK_DECLARE_FUNCTION

CK_DECLARE_FUNCTION(returnType, name), when followed by a parentheses-enclosed list of arguments and a semicolon, declares a Cryptoki API function in a Cryptoki library. returnType is the return type of the function, and name is its name. It is used in the following fashion:

CK_DECLARE_FUNCTION(CK_RV, C_Initialize)(   CK_VOID_PTR pReserved  );

CK_DECLARE_FUNCTION_POINTER

CK_DECLARE_FUNCTION_POINTER(returnType, name), when followed by a parentheses-enclosed list of arguments and a semicolon, declares a variable or type which is a pointer to a Cryptoki API function in a Cryptoki library. returnType is the return type of the function, and name is its name. It can be used in either of the following fashions to define a function pointer variable, myC_Initialize, which can point to a C_Initialize function in a Cryptoki library (note that neither of the following code snippets actually assigns a value to myC_Initialize):

CK_DECLARE_FUNCTION_POINTER(CK_RV, myC_Initialize)(   CK_VOID_PTR pReserved  );

or:

typedef CK_DECLARE_FUNCTION_POINTER(CK_RV, myC_InitializeType)(   CK_VOID_PTR pReserved  );
myC_InitializeType myC_Initialize;

CK_CALLBACK_FUNCTION

CK_CALLBACK_FUNCTION(returnType, name), when followed by a parentheses-enclosed list of arguments and a semicolon, declares a variable or type which is a pointer to an application callback function that can be used by a Cryptoki API function in a Cryptoki library. returnType is the return type of the function, and name is its name. It can be used in either of the following fashions to define a function pointer variable, myCallback, which can point to an application callback which takes arguments args and returns a CK_RV (note that neither of the following code snippets actually assigns a value to myCallback):

CK_CALLBACK_FUNCTION(CK_RV, myCallback)(args);

or:

typedef CK_CALLBACK_FUNCTION(CK_RV, myCallbackType)(args);
myCallbackType myCallback;

NULL_PTR

NULL_PTR is the value of a NULL pointer. In any ANSI C environment"and in many others as well"NULL_PTR should be defined simply as 0.

RSA Security Inc. Public-Key Cryptography Standards - PKCS#11 - v220