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| <h3 class="section">4.5 Integers</h3> |
| |
| <ul> |
| <li><cite>Any extended integer types that exist in the implementation (C99 6.2.5).</cite> |
| |
| <p>GCC does not support any extended integer types. |
| <!-- The __mode__ attribute might create types of precisions not --> |
| <!-- otherwise supported, but the syntax isn't right for use everywhere --> |
| <!-- the standard type names might be used. Predefined typedefs should --> |
| <!-- be used if any extended integer types are to be defined. The --> |
| <!-- __int128_t and __uint128_t typedefs are not extended integer types --> |
| <!-- as they are generally longer than the ABI-specified intmax_t. --> |
| |
| <li><cite>Whether signed integer types are represented using sign and magnitude, |
| two's complement, or one's complement, and whether the extraordinary value |
| is a trap representation or an ordinary value (C99 6.2.6.2).</cite> |
| |
| <p>GCC supports only two's complement integer types, and all bit patterns |
| are ordinary values. |
| |
| <li><cite>The rank of any extended integer type relative to another extended |
| integer type with the same precision (C99 6.3.1.1).</cite> |
| |
| <p>GCC does not support any extended integer types. |
| <!-- If it did, there would only be one of each precision and signedness. --> |
| |
| <li><cite>The result of, or the signal raised by, converting an integer to a |
| signed integer type when the value cannot be represented in an object of |
| that type (C90 6.2.1.2, C99 6.3.1.3).</cite> |
| |
| <p>For conversion to a type of width N, the value is reduced |
| modulo 2^N to be within range of the type; no signal is raised. |
| |
| <li><cite>The results of some bitwise operations on signed integers (C90 |
| 6.3, C99 6.5).</cite> |
| |
| <p>Bitwise operators act on the representation of the value including |
| both the sign and value bits, where the sign bit is considered |
| immediately above the highest-value value bit. Signed ‘<samp><span class="samp">>></span></samp>’ acts |
| on negative numbers by sign extension. |
| |
| <p>GCC does not use the latitude given in C99 only to treat certain |
| aspects of signed ‘<samp><span class="samp"><<</span></samp>’ as undefined, but this is subject to |
| change. |
| |
| <li><cite>The sign of the remainder on integer division (C90 6.3.5).</cite> |
| |
| <p>GCC always follows the C99 requirement that the result of division is |
| truncated towards zero. |
| |
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