Re: Any examples of Byte Ordering Functions

[James Rogers <jimmaureenrogers@att.net>]

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Hyman Rosen <hyrosen@mail.com> wrote in 
news:1066243458.911546@master.nyc.kbcfp.com:

> Larry Kilgallen wrote:
>>>Do Byte ordering functions (htonl, htons, ntohl, ntohs) exist in Ada?
>> Your question seems to me to indicate you are trying to program in C
>> using an Ada compiler.
> 
> So what's the Ada way of writing portable code that
> writes out and reads in 16-bit and 32-bit integers
> for an external data source that has a defined byte
> ordering?
> 

To quote from the Ada Language Reference Manual section 13.5:

For every specific record subtype S, the following attribute is defined: 

S�Bit_Order Denotes the bit ordering for the type of S. The value of this 
attribute is of type System.Bit_Order. Bit_Order may be specified for 
specific record types via an attribute_definition_clause; the expression of 
such a clause shall be static.

A bit ordering is a method of interpreting the meaning of the storage place 
attributes. High_Order_First (known in the vernacular as big endian) means 
that the first bit of a storage element (bit 0) is the most significant bit 
(interpreting the sequence of bits that represent a component as an 
unsigned integer value). Low_Order_First (known in the vernacular as little 
endian) means the opposite: the first bit is the least significant. 

Jim Rogers