For B-Format input conversion, w must be specified. The next w characters from the input stream are converted to a bit string, just as if they had appeared in a bit-string constant that was followed by B, B1, B2, B3, or B4. For a list of the valid characters and their translation to bits, see Bit-String Data. If the field of w characters contains an invalid character (including blank), the ERROR condition is signaled.