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The result of {{E1 << E2}} is {{E1}} left-shifted {{E2}} bit positions; vacated bits are filled with zeros. If {{E1}} has an unsigned type, the value of the result is {{E1 * 2 ^E2^}}, reduced modulo one more than the maximum value representable in the result type. As a result, left shift operations can result in an integer overflow condition (see \[[INT32-C|INT32-C. Ensure that integer operations do not result in an overflow]\]). If {{E1}} has a signed type and nonnegative value, and {{E1 * 2 ^E2^}} is representable in the result type, then that is the resulting value; otherwise, the behavior is undefined. |
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unsigned int si1, si2, result;
if ( (si2 < 0) || (si2 < 0) || (si2 >= sizeof(int)*CHAR_BIT) || (si1 > (INT_MAX / si2)) ) {
/* handle error condition */
}
result = si1 << si2;
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