FNC_CheckNullBitVector takes NullBitVector, indexValue, and bufSize as input and returns the value of the presence bit specified by indexValue in the NullBitVector.
After calling an FNC routine such as FNC_GetArrayElements, which sets presence information in a NullBitVector, you can call FNC_CheckNullBitVector to interpret the results of the NullBitVector returned by FNC_GetArrayElements.
For more information about using NullBitVectors, see Checking and Setting the NullBitVector.