Bit shifting a byte by more than 8 bit

Question

In here When converting from bytes buffer back to unsigned long int:

  unsigned long int anotherLongInt;

  anotherLongInt = ( (byteArray[0] << 24) 
           


        

Answer 1

The unsigned char's are implicitly cast to int's when shifting. Not sure to what type exactly it is cast, I thing that depends on the platform and the compiler. To get what you intend, it is safer to explicitly cast the bytes, that also makes it more portable and the reader immediately sees what you intend to do:

unsigned long int anotherLongInt;

anotherLongInt = ( ((unsigned long)byteArray[0] << 24) 
               + ((unsigned long)byteArray[1] << 16) 
               + ((unsigned long)byteArray[2] << 8) 
               + ((unsigned long)byteArray[3] ) );