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For Integers, the unsigned modifier defines the type to be unsigned. The default integer signedness outside bit-fields is signed, but can be set explicitly with signed modifier. By contrast, the C standard declares signed char, unsigned char, and char, to be three distinct types, but specifies that all three must have the same size and alignment.
C++ is also more strict in conversions to enums: ints cannot be implicitly converted to enums as in C. Also, enumeration constants (enum enumerators) are always of type int in C, whereas they are distinct types in C++ and may have a size different from that of int. [needs update] In C++ a const variable must be initialized; in C this is not ...
Additionally, POSIX includes ssize_t, which is a signed integer type of the same width as size_t. ptrdiff_t is a signed integer type used to represent the difference between pointers. It is guaranteed to be valid only against pointers of the same type; subtraction of pointers consisting of different types is implementation-defined.
If the source of the operation is an unsigned number, then zero extension is usually the correct way to move it to a larger field while preserving its numeric value, while sign extension is correct for signed numbers. In the x86 and x64 instruction sets, the movzx instruction ("move with zero extension") performs this function.
A signed number is represented similarly: Starting with an -bit two's complement representation, where is a multiple of 7, the number is broken into groups as for the unsigned encoding. For example, the signed number -123456 is encoded as 0xC0 0xBB 0x78:
Convert unsigned to an unsigned int8 (on the stack as int32) and throw an exception on overflow. Base instruction 0xB6 conv.ovf.u2: Convert to an unsigned int16 (on the stack as int32) and throw an exception on overflow. Base instruction 0x87 conv.ovf.u2.un: Convert unsigned to an unsigned int16 (on the stack as int32) and throw an exception on ...
In C and C++, constructs such as pointer type conversion and union — C++ adds reference type conversion and reinterpret_cast to this list — are provided in order to permit many kinds of type punning, although some kinds are not actually supported by the standard language.
It is also used in the WAP environment, where it is called variable length unsigned integer or uintvar. The DWARF debugging format [ 4 ] defines a variant called LEB128 (or ULEB128 for unsigned numbers), where the least significant group of 7 bits is encoded in the first byte, and the most significant bits are in the last byte (so effectively ...