The C standard requires that the basic int type is at least 16 bits. The same is true of unsigned int. So, either way, 1 << 16 is too large a shift if the integ

The C standard requires that the basic int type is at least 16 bits. The same is true of unsigned int. So, either way, 1 << 16 is too large a shift if the integer is 16 bits on your platform. In section J.2 Undefined Behaviour, the standard mentions that it's undefined when "an expression is shifted by a negative number or by an amount greater than or equal to the width of the promoted expression" [1] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf