Converting unsigned long array to unsigned char array

I'm working with an embedded system that transfers data over a 32-bit bus, so I have a variable defined as follows:

unsigned long UserData[4];

As you can tell, this would be 128-bits of data. After I get this data from the bus, I have a function that accepts 128-bits of data as an argument, but in the form of an unsigned character array as follows;

unsigned char FuncData[16];

// Both arguments are defined in the prototype as unsigned char's
RandomFunction(FuncData, UserData);

From looking at the above function, I want to input this UserData into the function - what would be the best way to typecast or convert this unsigned long array to an unsigned character array?

Thanks for the help, I greatly appreciate it!

I would type its name "UserData". (as in

Code:

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RandomFunction(FuncData, UserData);

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assuming there's no endianness issues). (If there are endianness issues, it was wrong to use an array of longs in the first place.)

It kind of depends on how you want to deal with the data. If you want to change each and every byte. Then (char*)longarray[3] should do the trick. If you want to treat each char value as an overflowed value, (IE the values SHOULD be between 0 and 255) then, well, don't do that :). (it can be done, but it is very hacky. you can add 4 to each indexing value to get it done, ie chararray[i + 4]; will get the job done (though, you'll have to start with -4)

As was stated, you'll need to watch out for the endians