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Front Page / Metafunctions / Bitwise Operations / shift_left |
template< typename T , typename Shift > struct shift_left { typedef unspecified type; };
Returns the result of bitwise shift left (<<) operation on T.
#include <boost/mpl/shift_left.hpp> #include <boost/mpl/bitwise.hpp>
Parameter | Requirement | Description |
---|---|---|
T | Integral Constant | A value to shift. |
Shift | Unsigned Integral Constant | A shift distance. |
[Note: The requirements listed in this specification are the ones imposed by the default implementation. See Numeric Metafunction concept for the details on how to provide an implementation for a user-defined numeric type that does not satisfy the Integral Constant requirements. — end note]
For arbitrary Integral Constant c and unsigned Integral Constant shift:
typedef shift_left<c,shift>::type r;
Return type: | Integral Constant. |
---|---|
Semantics: | Equivalent to typedef integral_c< c::value_type , ( c::value << shift::value ) > r; |
typedef shift_left<c,shift> r;
Return type: | Integral Constant. |
---|---|
Semantics: | Equivalent to struct r : shift_left<c,shift>::type {}; |
Amortized constant time.
typedef integral_c<unsigned,0> u0; typedef integral_c<unsigned,1> u1; typedef integral_c<unsigned,2> u2; typedef integral_c<unsigned,8> u8; BOOST_MPL_ASSERT_RELATION( (shift_left<u0,u0>::value), ==, 0 ); BOOST_MPL_ASSERT_RELATION( (shift_left<u1,u0>::value), ==, 1 ); BOOST_MPL_ASSERT_RELATION( (shift_left<u1,u1>::value), ==, 2 ); BOOST_MPL_ASSERT_RELATION( (shift_left<u2,u1>::value), ==, 4 ); BOOST_MPL_ASSERT_RELATION( (shift_left<u8,u1>::value), ==, 16 );