int fieldDecimal(cdbfapiPlus* handle, int fieldno);

The function fieldDecimal() returns a length of a fractinal part of a field by index.
It is suitable only for Numeric, Float, Double fields. For other types it returns 0.
It also returns 0 if index is out of range.

    // your code
    for ( i=0; i < fieldCount(dbf); i++)
        printf( "%d\n", fieldDecimal( dbf, i ) );
    // your code