NULL-Valued Pointer

The NULL-valued pointer, as defined in stddef.h, is a DataBlade API constant that represents an initialized pointer. NULL is usually represented as zero (0) for a C pointer. However zero does not always represent NULL. Use the keyword NULL in your DataBlade API code to initialize pointers, as the following line shows:

MI_ROW *row = NULL;

In addition, the DataBlade API uses the NULL-value pointer for the following:

• To signify a default value for arguments in many DataBlade API functions
• To indicate an unsuccessful execution of a DataBlade API function that, when successful, returns a pointer to some value